EOS/Models/NpgSqlHelper.cs
Nidhi Bhargava f0c1ab20e1 code push
2025-09-04 16:25:07 +05:30

1380 lines
73 KiB
C#

//===============================================================================
// NpgsqlHelper based on Microsoft Data Access Application Block (DAAB) for .NET
// http://msdn.microsoft.com/library/en-us/dnbda/html/daab-rm.asp
//
// NpgsqlHelper.cs
//
// This file contains the implementations of the NpgsqlHelper and NpgsqlHelperParameterCache
// classes.
//
// The DAAB for MS Ole Db access for Oracle has been tested in the context of this Nile implementation,
// but has not undergone the generic functional testing that the Npgsql version has gone through.
// You can use it in other .NET applications using Oracle databases. For complete docs explaining how to use
// and how it's built go to the originl appblock link.
// For this sample, the code resides in the Nile namespaces not the Microsoft.ApplicationBlocks namespace
//==============================================================================
using System;
using System.Data;
using System.Xml;
using Npgsql;
using System.Collections;
//namespace SharpContent.ApplicationBlocks.Data
namespace DBHelper
{
/// <summary>
/// The NpgsqlHelper class is intended to encapsulate high performance, scalable best practices for
/// common uses of NpgsqlClient.
/// </summary>
public sealed class NpgSqlHelper
{
#region private utility methods & constructors
//Since this class provides only static methods, make the default constructor private to prevent
//instances from being created with "new NpgsqlHelper()".
private NpgSqlHelper() { }
/// <summary>
/// This method is used to attach array's of NpgsqlParameters to an NpgsqlCommand.
///
/// This method will assign a value of DbNull to any parameter with a direction of
/// InputOutput and a value of null.
///
/// This behavior will prevent default values from being used, but
/// this will be the less common case than an intended pure output parameter (derived as InputOutput)
/// where the user provided no input value.
/// </summary>
/// <param name="command">The command to which the parameters will be added</param>
/// <param name="commandParameters">an array of NpgsqlParameters tho be added to command</param>
private static void AttachParameters(NpgsqlCommand command, NpgsqlParameter[] commandParameters)
{
foreach (NpgsqlParameter p in commandParameters)
{
//check for derived output value with no value assigned
if ((p.Direction == ParameterDirection.InputOutput) && (p.Value == null))
{
p.Value = DBNull.Value;
}
command.Parameters.Add(p);
}
}
/// <summary>
/// This method assigns an array of values to an array of NpgsqlParameters.
/// </summary>
/// <param name="commandParameters">array of NpgsqlParameters to be assigned values</param>
/// <param name="parameterValues">array of objects holding the values to be assigned</param>
private static void AssignParameterValues(NpgsqlParameter[] commandParameters, object[] parameterValues)
{
if ((commandParameters == null) || (parameterValues == null))
{
//do nothing if we get no data
return;
}
// we must have the same number of values as we pave parameters to put them in
if (commandParameters.Length != parameterValues.Length)
{
throw new ArgumentException("Parameter count does not match Parameter Value count.");
}
//iterate through the NpgsqlParameters, assigning the values from the corresponding position in the
//value array
for (int i = 0, j = commandParameters.Length; i < j; i++)
{
commandParameters[i].Value = parameterValues[i];
}
}
/// <summary>
/// This method opens (if necessary) and assigns a connection, transaction, command type and parameters
/// to the provided command.
/// </summary>
/// <param name="command">the NpgsqlCommand to be prepared</param>
/// <param name="connection">a valid NpgsqlConnection, on which to execute this command</param>
/// <param name="transaction">a valid NpgsqlTransaction, or 'null'</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <param name="commandParameters">an array of NpgsqlParameters to be associated with the command or 'null' if no parameters are required</param>
private static void PrepareCommand(NpgsqlCommand command, NpgsqlConnection connection, NpgsqlTransaction transaction, CommandType commandType, string commandText, NpgsqlParameter[] commandParameters)
{
//if the provided connection is not open, we will open it
if (connection.State != ConnectionState.Open)
{
connection.Open();
}
//associate the connection with the command
command.Connection = connection;
//set the command text (stored procedure name or Npgsql statement)
command.CommandText = commandText;
//if we were provided a transaction, assign it.
if (transaction != null)
{
command.Transaction = transaction;
}
//set the command type
command.CommandType = commandType;
//attach the command parameters if they are provided
if (commandParameters != null)
{
AttachParameters(command, commandParameters);
}
return;
}
#endregion private utility methods & constructors
#region ExecuteNonQuery
/// <summary>
/// Execute an NpgsqlCommand (that returns no resultset and takes no parameters) against the database specified in
/// the connection string.
/// </summary>
/// <remarks>
/// e.g.:
/// int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders");
/// </remarks>
/// <param name="connectionString">a valid connection string for an NpgsqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <returns>an int representing the number of rows affected by the command</returns>
public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of NpgsqlParameters
return ExecuteNonQuery(connectionString, commandType, commandText, (NpgsqlParameter[])null);
}
/// <summary>
/// Execute an NpgsqlCommand (that returns no resultset) against the database specified in the connection string
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new NpgsqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">a valid connection string for a NpgsqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <param name="commandParameters">an array of NpgsqlParameters used to execute the command</param>
/// <returns>an int representing the number of rows affected by the command</returns>
public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText, params NpgsqlParameter[] commandParameters)
{
//create & open an NpgsqlConnection, and dispose of it after we are done.
//using (NpgsqlConnection cn = new NpgsqlConnection(connectionString))
//{
// cn.Open();
// //call the overload that takes a connection in place of the connection string
// return ExecuteNonQuery(cn, commandType, commandText, commandParameters);
//}
NpgsqlConnection cn = null;
try
{
cn = new NpgsqlConnection(connectionString);
if (cn.State != ConnectionState.Open)
cn.Open();
////call the overload that takes a connection in place of the connection string
return ExecuteNonQuery(cn, commandType, commandText, commandParameters);
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
finally
{
if (cn.State != ConnectionState.Closed)
cn.Close();
}
}
/// <summary>
/// Execute a stored procedure via an NpgsqlCommand (that returns no resultset) against the database specified in
/// the connection string using the provided parameter values. This method will query the database to discover the parameters for the
/// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
/// </summary>
/// <remarks>
/// This method provides no access to output parameters or the stored procedure's return value parameter.
///
/// e.g.:
/// int result = ExecuteNonQuery(connString, "PublishOrders", 24, 36);
/// </remarks>
/// <param name="connectionString">a valid connection string for a NpgsqlConnection</param>
/// <param name="spName">the name of the stored prcedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>an int representing the number of rows affected by the command</returns>
public static int ExecuteNonQuery(string connectionString, string spName, params object[] parameterValues)
{
//if we got parameter values, we need to figure out where they go
if ((parameterValues != null) && (parameterValues.Length > 0))
{
//pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
NpgsqlParameter[] commandParameters = NpgsqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
//assign the provided values to these parameters based on parameter order
AssignParameterValues(commandParameters, parameterValues);
//call the overload that takes an array of NpgsqlParameters
return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName);
}
}
/// <summary>
/// Execute an NpgsqlDbCommand (that returns no resultset and takes no parameters) against the provided NpgsqlConnection.
/// </summary>
/// <remarks>
/// e.g.:
/// int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders");
/// </remarks>
/// <param name="connection">a valid NpgsqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <returns>an int representing the number of rows affected by the command</returns>
public static int ExecuteNonQuery(NpgsqlConnection connection, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of NpgsqlParameters
return ExecuteNonQuery(connection, commandType, commandText, (NpgsqlParameter[])null);
}
/// <summary>
/// Execute an NpgsqlCommand (that returns no resultset) against the specified NpgsqlConnection
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders", new NpgsqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connection">a valid NpgsqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <param name="commandParameters">an array of NpgsqlParamters used to execute the command</param>
/// <returns>an int representing the number of rows affected by the command</returns>
public static int ExecuteNonQuery(NpgsqlConnection connection, CommandType commandType, string commandText, params NpgsqlParameter[] commandParameters)
{
//create a command and prepare it for execution
NpgsqlCommand cmd = new NpgsqlCommand();
PrepareCommand(cmd, connection, (NpgsqlTransaction)null, commandType, commandText, commandParameters);
//finally, execute the command.
return cmd.ExecuteNonQuery();
}
/// <summary>
/// Execute a stored procedure via an NpgsqlCommand (that returns no resultset) against the specified NpgsqlConnection
/// using the provided parameter values. This method will query the database to discover the parameters for the
/// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
/// </summary>
/// <remarks>
/// This method provides no access to output parameters or the stored procedure's return value parameter.
///
/// e.g.:
/// int result = ExecuteNonQuery(conn, "PublishOrders", 24, 36);
/// </remarks>
/// <param name="connection">a valid NpgsqlConnection</param>
/// <param name="spName">the name of the stored prcedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>an int representing the number of rows affected by the command</returns>
public static int ExecuteNonQuery(NpgsqlConnection connection, string spName, params object[] parameterValues)
{
//if we got parameter values, we need to figure out where they go
if ((parameterValues != null) && (parameterValues.Length > 0))
{
//pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
NpgsqlParameter[] commandParameters = NpgsqlHelperParameterCache.GetSpParameterSet(connection.ConnectionString, spName);
//assign the provided values to these parameters based on parameter order
AssignParameterValues(commandParameters, parameterValues);
//call the overload that takes an array of NpgsqlParameters
return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName);
}
}
/// <summary>
/// Execute an NpgsqlCommand (that returns no resultset and takes no parameters) against the provided NpgsqlTransaction.
/// </summary>
/// <remarks>
/// e.g.:
/// int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders");
/// </remarks>
/// <param name="transaction">a valid NpgsqlTransaction</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <returns>an int representing the number of rows affected by the command</returns>
public static int ExecuteNonQuery(NpgsqlTransaction transaction, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of NpgsqlParameters
return ExecuteNonQuery(transaction, commandType, commandText, (NpgsqlParameter[])null);
}
/// <summary>
/// Execute an NpgsqlCommand (that returns no resultset) against the specified NpgsqlTransaction
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "GetOrders", new NpgsqlParameter("@prodid", 24));
/// </remarks>
/// <param name="transaction">a valid NpgsqlTransaction</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <param name="commandParameters">an array of NpgsqlParamters used to execute the command</param>
/// <returns>an int representing the number of rows affected by the command</returns>
public static int ExecuteNonQuery(NpgsqlTransaction transaction, CommandType commandType, string commandText, params NpgsqlParameter[] commandParameters)
{
//create a command and prepare it for execution
NpgsqlCommand cmd = new NpgsqlCommand();
PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);
//finally, execute the command.
return cmd.ExecuteNonQuery();
}
/// <summary>
/// Execute a stored procedure via an NpgsqlCommand (that returns no resultset) against the specified
/// NpgsqlTransaction using the provided parameter values. This method will query the database to discover the parameters for the
/// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
/// </summary>
/// <remarks>
/// This method provides no access to output parameters or the stored procedure's return value parameter.
///
/// e.g.:
/// int result = ExecuteNonQuery(conn, trans, "PublishOrders", 24, 36);
/// </remarks>
/// <param name="transaction">a valid NpgsqlTransaction</param>
/// <param name="spName">the name of the stored procedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>an int representing the number of rows affected by the command</returns>
public static int ExecuteNonQuery(NpgsqlTransaction transaction, string spName, params object[] parameterValues)
{
//if we got parameter values, we need to figure out where they go
if ((parameterValues != null) && (parameterValues.Length > 0))
{
//pull the parameters for this stored procedure from the parameter cache (or discover them & populet the cache)
NpgsqlParameter[] commandParameters = NpgsqlHelperParameterCache.GetSpParameterSet(transaction.Connection.ConnectionString, spName);
//assign the provided values to these parameters based on parameter order
AssignParameterValues(commandParameters, parameterValues);
//call the overload that takes an array of NpgsqlParameters
return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName);
}
}
#endregion ExecuteNonQuery
#region ExecuteDataSet
/// <summary>
/// Execute an NpgsqlCommand (that returns a resultset and takes no parameters) against the database specified in
/// the connection string.
/// </summary>
/// <remarks>
/// e.g.:
/// DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders");
/// </remarks>
/// <param name="connectionString">a valid connection string for an NpgsqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <returns>a dataset containing the resultset generated by the command</returns>
public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of NpgsqlParameters
return ExecuteDataset(connectionString, commandType, commandText, (NpgsqlParameter[])null);
}
/// <summary>
/// Execute an NpgsqlCommand (that returns a resultset) against the database specified in the connection string
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders", new NpgsqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">a valid connection string for an NpgsqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <param name="commandParameters">an array of NpgsqlParamters used to execute the command</param>
/// <returns>a dataset containing the resultset generated by the command</returns>
public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText, params NpgsqlParameter[] commandParameters)
{
//create & open an NpgsqlConnection, and dispose of it after we are done.
//using (NpgsqlConnection cn = new NpgsqlConnection(connectionString))
//{
// //cn.Open();//change by jitendra
// //call the overload that takes a connection in place of the connection string
// return ExecuteDataset(cn, commandType, commandText, commandParameters);
//}
NpgsqlConnection cn=null;
try
{
cn = new NpgsqlConnection(connectionString);
//call the overload that takes a connection in place of the connection string
return ExecuteDataset(cn, commandType, commandText, commandParameters);
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
finally
{
if (cn.State != ConnectionState.Closed)
cn.Close();
}
}
/// <summary>
/// Execute a stored procedure via an NpgsqlCommand (that returns a resultset) against the database specified in
/// the conneciton string using the provided parameter values. This method will query the database to discover the parameters for the
/// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
/// </summary>
/// <remarks>
/// This method provides no access to output parameters or the stored procedure's return value parameter.
///
/// e.g.:
/// DataSet ds = ExecuteDataset(connString, "GetOrders", 24, 36);
/// </remarks>
/// <param name="connectionString">a valid connection string for an NpgsqlConnection</param>
/// <param name="spName">the name of the stored procedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>a dataset containing the resultset generated by the command</returns>
public static DataSet ExecuteDataset(string connectionString, string spName, params object[] parameterValues)
{
//if we got parameter values, we need to figure out where they go
if ((parameterValues != null) && (parameterValues.Length > 0))
{
//pull the parameters for this stored procedure from the parameter cache (or discover them & populet the cache)
NpgsqlParameter[] commandParameters = NpgsqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
//assign the provided values to these parameters based on parameter order
AssignParameterValues(commandParameters, parameterValues);
//call the overload that takes an array of NpgsqlParameters
return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName);
}
}
/// <summary>
/// Execute an NpgsqlCommand (that returns a resultset and takes no parameters) against the provided NpgsqlConnection.
/// </summary>
/// <remarks>
/// e.g.:
/// DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders");
/// </remarks>
/// <param name="connection">a valid NpgsqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <returns>a dataset containing the resultset generated by the command</returns>
public static DataSet ExecuteDataset(NpgsqlConnection connection, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of NpgsqlParameters
return ExecuteDataset(connection, commandType, commandText, (NpgsqlParameter[])null);
}
/// <summary>
/// Execute an NpgsqlCommand (that returns a resultset) against the specified NpgsqlConnection
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders", new NpgsqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connection">a valid NpgsqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <param name="commandParameters">an array of NpgsqlParamters used to execute the command</param>
/// <returns>a dataset containing the resultset generated by the command</returns>
public static DataSet ExecuteDataset(NpgsqlConnection connection, CommandType commandType, string commandText, params NpgsqlParameter[] commandParameters)
{
////create a command and prepare it for execution
//NpgsqlCommand cmd = new NpgsqlCommand();
//PrepareCommand(cmd, connection, (NpgsqlTransaction)null, commandType, commandText, commandParameters);
////create the DataAdapter & DataSet
//NpgsqlDataAdapter da = new NpgsqlDataAdapter(cmd);
//DataSet ds = new DataSet();
////fill the DataSet using default values for DataTable names, etc.
//da.Fill(ds);
////return the dataset
//return ds;
// Modified by Kapil
//create a command and prepare it for execution
//SqlCommand cmd = new SqlCommand();
//cmd.CommandText = commandText;
//cmd.CommandType = commandType;
// PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters);
//AttachParameters(cmd, commandParameters);
NpgsqlDataAdapter adp = new NpgsqlDataAdapter(commandText, connection);
adp.SelectCommand.CommandType = commandType;
if (commandParameters != null)
{
foreach (NpgsqlParameter p in commandParameters)
{
//check for derived output value with no value assigned
if ((p.Direction == ParameterDirection.InputOutput) && (p.Value == null))
{
p.Value = DBNull.Value;
}
adp.SelectCommand.Parameters.Add(p);
}
}
//create the DataAdapter & DataSet
//SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
//fill the DataSet using default values for DataTable names, etc.
adp.Fill(ds);
//return the dataset
return ds;
}
/// <summary>
/// Execute a stored procedure via an NpgsqlCommand (that returns a resultset) against the specified NpgsqlConnection
/// using the provided parameter values. This method will query the database to discover the parameters for the
/// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
/// </summary>
/// <remarks>
/// This method provides no access to output parameters or the stored procedure's return value parameter.
///
/// e.g.:
/// DataSet ds = ExecuteDataset(conn, "GetOrders", 24, 36);
/// </remarks>
/// <param name="connection">a valid NpgsqlConnection</param>
/// <param name="spName">the name of the stored prcedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>a dataset containing the resultset generated by the command</returns>
public static DataSet ExecuteDataset(NpgsqlConnection connection, string spName, params object[] parameterValues)
{
//if we got parameter values, we need to figure out where they go
if ((parameterValues != null) && (parameterValues.Length > 0))
{
//pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
NpgsqlParameter[] commandParameters = NpgsqlHelperParameterCache.GetSpParameterSet(connection.ConnectionString, spName);
//assign the provided values to these parameters based on parameter order
AssignParameterValues(commandParameters, parameterValues);
//call the overload that takes an array of NpgsqlParameters
return ExecuteDataset(connection, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteDataset(connection, CommandType.StoredProcedure, spName);
}
}
/// <summary>
/// Execute an NpgsqlCommand (that returns a resultset and takes no parameters) against the provided NpgsqlTransaction.
/// </summary>
/// <remarks>
/// e.g.:
/// DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders");
/// </remarks>
/// <param name="transaction">a valid NpgsqlTransaction</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <returns>a dataset containing the resultset generated by the command</returns>
public static DataSet ExecuteDataset(NpgsqlTransaction transaction, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of NpgsqlParameters
return ExecuteDataset(transaction, commandType, commandText, (NpgsqlParameter[])null);
}
/// <summary>
/// Execute an NpgsqlCommand (that returns a resultset) against the specified NpgsqlTransaction
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders", new NpgsqlParameter("@prodid", 24));
/// </remarks>
/// <param name="transaction">a valid NpgsqlTransaction</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <param name="commandParameters">an array of NpgsqlParamters used to execute the command</param>
/// <returns>a dataset containing the resultset generated by the command</returns>
public static DataSet ExecuteDataset(NpgsqlTransaction transaction, CommandType commandType, string commandText, params NpgsqlParameter[] commandParameters)
{
//create a command and prepare it for execution
NpgsqlCommand cmd = new NpgsqlCommand();
PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);
//create the DataAdapter & DataSet
NpgsqlDataAdapter da = new NpgsqlDataAdapter(cmd);
DataSet ds = new DataSet();
//fill the DataSet using default values for DataTable names, etc.
da.Fill(ds);
//return the dataset
return ds;
}
/// <summary>
/// Execute a stored procedure via an NpgsqlCommand (that returns a resultset) against the specified
/// NpgsqlTransaction using the provided parameter values. This method will query the database to discover the parameters for the
/// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
/// </summary>
/// <remarks>
/// This method provides no access to output parameters or the stored procedure's return value parameter.
///
/// e.g.:
/// DataSet ds = ExecuteDataset(trans, "GetOrders", 24, 36);
/// </remarks>
/// <param name="transaction">a valid NpgsqlTransaction</param>
/// <param name="spName">the name of the stored prcedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>a dataset containing the resultset generated by the command</returns>
public static DataSet ExecuteDataset(NpgsqlTransaction transaction, string spName, params object[] parameterValues)
{
//if we got parameter values, we need to figure out where they go
if ((parameterValues != null) && (parameterValues.Length > 0))
{
//pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
NpgsqlParameter[] commandParameters = NpgsqlHelperParameterCache.GetSpParameterSet(transaction.Connection.ConnectionString, spName);
//assign the provided values to these parameters based on parameter order
AssignParameterValues(commandParameters, parameterValues);
//call the overload that takes an array of NpgsqlParameters
return ExecuteDataset(transaction, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteDataset(transaction, CommandType.StoredProcedure, spName);
}
}
#endregion ExecuteDataSet
#region ExecuteReader
/// <summary>
/// this enum is used to indicate weather the connection was provided by the caller, or created by NpgsqlHelper, so that
/// we can set the appropriate CommandBehavior when calling ExecuteReader()
/// </summary>
private enum NpgsqlConnectionOwnership
{
/// <summary>Connection is owned and managed by NpgsqlHelper</summary>
Internal,
/// <summary>Connection is owned and managed by the caller</summary>
External
}
/// <summary>
/// Create and prepare an NpgsqlCommand, and call ExecuteReader with the appropriate CommandBehavior.
/// </summary>
/// <remarks>
/// If we created and opened the connection, we want the connection to be closed when the DataReader is closed.
///
/// If the caller provided the connection, we want to leave it to them to manage.
/// </remarks>
/// <param name="connection">a valid NpgsqlConnection, on which to execute this command</param>
/// <param name="transaction">a valid NpgsqlTransaction, or 'null'</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <param name="commandParameters">an array of NpgsqlParameters to be associated with the command or 'null' if no parameters are required</param>
/// <param name="connectionOwnership">indicates whether the connection parameter was provided by the caller, or created by NpgsqlHelper</param>
/// <returns>NpgsqlDataReader containing the results of the command</returns>
private static NpgsqlDataReader ExecuteReader(NpgsqlConnection connection, NpgsqlTransaction transaction, CommandType commandType, string commandText, NpgsqlParameter[] commandParameters, NpgsqlConnectionOwnership connectionOwnership)
{
//create a command and prepare it for execution
NpgsqlCommand cmd = new NpgsqlCommand();
PrepareCommand(cmd, connection, transaction, commandType, commandText, commandParameters);
//create a reader
NpgsqlDataReader dr;
// call ExecuteReader with the appropriate CommandBehavior
if (connectionOwnership == NpgsqlConnectionOwnership.External)
{
dr = cmd.ExecuteReader();
}
else
{
dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
}
return dr;
}
/// <summary>
/// Execute an NpgsqlCommand (that returns a resultset and takes no parameters) against the database specified in
/// the connection string.
/// </summary>
/// <remarks>
/// e.g.:
/// NpgsqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders");
/// </remarks>
/// <param name="connectionString">a valid connection string for an NpgsqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <returns>an NpgsqlDataReader containing the resultset generated by the command</returns>
public static NpgsqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of NpgsqlParameters
return ExecuteReader(connectionString, commandType, commandText, (NpgsqlParameter[])null);
}
/// <summary>
/// Execute an NpgsqlCommand (that returns a resultset) against the database specified in the connection string
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// NpgsqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders", new NpgsqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">a valid connection string for an NpgsqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <param name="commandParameters">an array of NpgsqlParameters used to execute the command</param>
/// <returns>an NpgsqlDataReader containing the resultset generated by the command</returns>
public static NpgsqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText, params NpgsqlParameter[] commandParameters)
{
//create & open an NpgsqlbConnection
NpgsqlConnection cn = new NpgsqlConnection(connectionString);
if (cn.State != ConnectionState.Open)
cn.Open();
try
{
//call the private overload that takes an internally owned connection in place of the connection string
return ExecuteReader(cn, null, commandType, commandText, commandParameters, NpgsqlConnectionOwnership.Internal);
}
catch
{
//if we fail to return the NpgsqlDataReader, we neeed to close the connection ourselves
cn.Close();
throw;
}
finally
{
}
}
/// <summary>
/// Execute a stored procedure via an NpgsqlCommand (that returns a resultset) against the database specified in
/// the connection string using the provided parameter values. This method will query the database to discover the parameters for the
/// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
/// </summary>
/// <remarks>
/// This method provides no access to output parameters or the stored procedure's return value parameter.
///
/// e.g.:
/// NpgsqlDataReader dr = ExecuteReader(connString, "GetOrders", 24, 36);
/// </remarks>
/// <param name="connectionString">a valid connection string for an NpgsqlConnection</param>
/// <param name="spName">the name of the stored prcedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>an NpgsqlDataReader containing the resultset generated by the command</returns>
public static NpgsqlDataReader ExecuteReader(string connectionString, string spName, params object[] parameterValues)
{
//if we got parameter values, we need to figure out where they go
if ((parameterValues != null) && (parameterValues.Length > 0))
{
//pull the parameters for this stored procedure from the parameter cache (or discover them & populate the cache)
NpgsqlParameter[] commandParameters = NpgsqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
//assign the provided values to these parameters based on parameter order
AssignParameterValues(commandParameters, parameterValues);
//call the overload that takes an array of NpgsqlParameters
return ExecuteReader(connectionString, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteReader(connectionString, CommandType.StoredProcedure, spName);
}
}
/// <summary>
/// Execute an NpgsqlCommand (that returns a resultset and takes no parameters) against the provided NpgsqlConnection.
/// </summary>
/// <remarks>
/// e.g.:
/// NpgsqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders");
/// </remarks>
/// <param name="connection">a valid NpgsqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <returns>an NpgsqlDataReader containing the resultset generated by the command</returns>
public static NpgsqlDataReader ExecuteReader(NpgsqlConnection connection, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of NpgsqlParameters
return ExecuteReader(connection, commandType, commandText, (NpgsqlParameter[])null);
}
/// <summary>
/// Execute an NpgsqlCommand (that returns a resultset) against the specified NpgsqlConnection
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// NpgsqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders", new NpgsqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connection">a valid NpgsqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <param name="commandParameters">an array of NpgsqlParamters used to execute the command</param>
/// <returns>an NpgsqlDataReader containing the resultset generated by the command</returns>
public static NpgsqlDataReader ExecuteReader(NpgsqlConnection connection, CommandType commandType, string commandText, params NpgsqlParameter[] commandParameters)
{
//pass through the call to the private overload using a null transaction value and an externally owned connection
return ExecuteReader(connection, (NpgsqlTransaction)null, commandType, commandText, commandParameters, NpgsqlConnectionOwnership.External);
}
/// <summary>
/// Execute a stored procedure via an NpgsqlCommand (that returns a resultset) against the specified NpgsqlConnection
/// using the provided parameter values. This method will query the database to discover the parameters for the
/// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
/// </summary>
/// <remarks>
/// This method provides no access to output parameters or the stored procedure's return value parameter.
///
/// e.g.:
/// NpgsqlDataReader dr = ExecuteReader(conn, "GetOrders", 24, 36);
/// </remarks>
/// <param name="connection">a valid NpgsqlConnection</param>
/// <param name="spName">the name of the stored procedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>an NpgsqlDataReader containing the resultset generated by the command</returns>
public static NpgsqlDataReader ExecuteReader(NpgsqlConnection connection, string spName, params object[] parameterValues)
{
//if we got parameter values, we need to figure out where they go
if ((parameterValues != null) && (parameterValues.Length > 0))
{
NpgsqlParameter[] commandParameters = NpgsqlHelperParameterCache.GetSpParameterSet(connection.ConnectionString, spName);
AssignParameterValues(commandParameters, parameterValues);
return ExecuteReader(connection, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteReader(connection, CommandType.StoredProcedure, spName);
}
}
/// <summary>
/// Execute an NpgsqlCommand (that returns a resultset and takes no parameters) against the provided NpgsqlTransaction.
/// </summary>
/// <remarks>
/// e.g.:
/// NpgsqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders");
/// </remarks>
/// <param name="transaction">a valid NpgsqlTransaction</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <returns>an NpgsqlDataReader containing the resultset generated by the command</returns>
public static NpgsqlDataReader ExecuteReader(NpgsqlTransaction transaction, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of NpgsqlParameters
return ExecuteReader(transaction, commandType, commandText, (NpgsqlParameter[])null);
}
/// <summary>
/// Execute an NpgsqlCommand (that returns a resultset) against the specified NpgsqlTransaction
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// NpgsqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders", new NpgsqlParameter("@prodid", 24));
/// </remarks>
/// <param name="transaction">a valid NpgsqlTransaction</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or PL/Npgsql command</param>
/// <param name="commandParameters">an array of NpgsqlParameters used to execute the command</param>
/// <returns>an NpgsqlDataReader containing the resultset generated by the command</returns>
public static NpgsqlDataReader ExecuteReader(NpgsqlTransaction transaction, CommandType commandType, string commandText, params NpgsqlParameter[] commandParameters)
{
//pass through to private overload, indicating that the connection is owned by the caller
return ExecuteReader(transaction.Connection, transaction, commandType, commandText, commandParameters, NpgsqlConnectionOwnership.External);
}
/// <summary>
/// Execute a stored procedure via an NpgsqlCommand (that returns a resultset) against the specified
/// NpgsqlTransaction using the provided parameter values. This method will query the database to discover the parameters for the
/// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
/// </summary>
/// <remarks>
/// This method provides no access to output parameters or the stored procedure's return value parameter.
///
/// e.g.:
/// NpgsqlDataReader dr = ExecuteReader(trans, "GetOrders", 24, 36);
/// </remarks>
/// <param name="transaction">a valid NpgsqlTransaction</param>
/// <param name="spName">the name of the stored prcedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>an NpgsqlDataReader containing the resultset generated by the command</returns>
public static NpgsqlDataReader ExecuteReader(NpgsqlTransaction transaction, string spName, params object[] parameterValues)
{
//if we got parameter values, we need to figure out where they go
if ((parameterValues != null) && (parameterValues.Length > 0))
{
NpgsqlParameter[] commandParameters = NpgsqlHelperParameterCache.GetSpParameterSet(transaction.Connection.ConnectionString, spName);
AssignParameterValues(commandParameters, parameterValues);
return ExecuteReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteReader(transaction, CommandType.StoredProcedure, spName);
}
}
#endregion ExecuteReader
#region ExecuteScalar
/// <summary>
/// Execute a NpgsqlCommand (that returns a 1x1 resultset and takes no parameters) against the database specified in
/// the connection string.
/// </summary>
/// <remarks>
/// e.g.:
/// int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount");
/// </remarks>
/// <param name="connectionString">a valid connection string for a NpgsqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-Npgsql command</param>
/// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of NpgsqlParameters
return ExecuteScalar(connectionString, commandType, commandText, (NpgsqlParameter[])null);
}
/// <summary>
/// Execute a NpgsqlCommand (that returns a 1x1 resultset) against the database specified in the connection string
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount", new NpgsqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">a valid connection string for a NpgsqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-Npgsql command</param>
/// <param name="commandParameters">an array of NpgsqlParamters used to execute the command</param>
/// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText, params NpgsqlParameter[] commandParameters)
{
//create & open a NpgsqlConnection, and dispose of it after we are done.
//using (NpgsqlConnection cn = new NpgsqlConnection(connectionString))
//{
// cn.Open();
// //call the overload that takes a connection in place of the connection string
// return ExecuteScalar(cn, commandType, commandText, commandParameters);
//}
NpgsqlConnection cn = null;
try
{
cn = new NpgsqlConnection(connectionString);
//cn.Open();
//call the overload that takes a connection in place of the connection string
return ExecuteScalar(cn, commandType, commandText, commandParameters);
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
finally
{
cn.Close();
}
}
/// <summary>
/// Execute a stored procedure via a NpgsqlCommand (that returns a 1x1 resultset) against the database specified in
/// the conneciton string using the provided parameter values. This method will query the database to discover the parameters for the
/// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
/// </summary>
/// <remarks>
/// This method provides no access to output parameters or the stored procedure's return value parameter.
///
/// e.g.:
/// int orderCount = (int)ExecuteScalar(connString, "GetOrderCount", 24, 36);
/// </remarks>
/// <param name="connectionString">a valid connection string for a NpgsqlConnection</param>
/// <param name="spName">the name of the stored prcedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(string connectionString, string spName, params object[] parameterValues)
{
//if we got parameter values, we need to figure out where they go
if ((parameterValues != null) && (parameterValues.Length > 0))
{
//pull the parameters for this stored procedure from the parameter cache (or discover them & populet the cache)
NpgsqlParameter[] commandParameters = NpgsqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
//assign the provided values to these parameters based on parameter order
AssignParameterValues(commandParameters, parameterValues);
//call the overload that takes an array of NpgsqlParameters
return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName);
}
}
/// <summary>
/// Execute a NpgsqlCommand (that returns a 1x1 resultset and takes no parameters) against the provided NpgsqlConnection.
/// </summary>
/// <remarks>
/// e.g.:
/// int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount");
/// </remarks>
/// <param name="connection">a valid NpgsqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-Npgsql command</param>
/// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(NpgsqlConnection connection, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of NpgsqlParameters
return ExecuteScalar(connection, commandType, commandText, (NpgsqlParameter[])null);
}
/// <summary>
/// Execute a NpgsqlCommand (that returns a 1x1 resultset) against the specified NpgsqlConnection
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount", new NpgsqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connection">a valid NpgsqlConnection</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-Npgsql command</param>
/// <param name="commandParameters">an array of NpgsqlParamters used to execute the command</param>
/// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(NpgsqlConnection connection, CommandType commandType, string commandText, params NpgsqlParameter[] commandParameters)
{
//create a command and prepare it for execution
NpgsqlCommand cmd = new NpgsqlCommand();
PrepareCommand(cmd, connection, (NpgsqlTransaction)null, commandType, commandText, commandParameters);
//execute the command & return the results
return cmd.ExecuteScalar();
}
/// <summary>
/// Execute a stored procedure via a NpgsqlCommand (that returns a 1x1 resultset) against the specified NpgsqlConnection
/// using the provided parameter values. This method will query the database to discover the parameters for the
/// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
/// </summary>
/// <remarks>
/// This method provides no access to output parameters or the stored procedure's return value parameter.
///
/// e.g.:
/// int orderCount = (int)ExecuteScalar(conn, "GetOrderCount", 24, 36);
/// </remarks>
/// <param name="connection">a valid NpgsqlConnection</param>
/// <param name="spName">the name of the stored prcedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(NpgsqlConnection connection, string spName, params object[] parameterValues)
{
//if we got parameter values, we need to figure out where they go
if ((parameterValues != null) && (parameterValues.Length > 0))
{
//pull the parameters for this stored procedure from the parameter cache (or discover them & populet the cache)
NpgsqlParameter[] commandParameters = NpgsqlHelperParameterCache.GetSpParameterSet(connection.ConnectionString, spName);
//assign the provided values to these parameters based on parameter order
AssignParameterValues(commandParameters, parameterValues);
//call the overload that takes an array of NpgsqlParameters
return ExecuteScalar(connection, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteScalar(connection, CommandType.StoredProcedure, spName);
}
}
/// <summary>
/// Execute a NpgsqlCommand (that returns a 1x1 resultset and takes no parameters) against the provided NpgsqlTransaction.
/// </summary>
/// <remarks>
/// e.g.:
/// int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount");
/// </remarks>
/// <param name="transaction">a valid NpgsqlTransaction</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-Npgsql command</param>
/// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(NpgsqlTransaction transaction, CommandType commandType, string commandText)
{
//pass through the call providing null for the set of NpgsqlParameters
return ExecuteScalar(transaction, commandType, commandText, (NpgsqlParameter[])null);
}
/// <summary>
/// Execute a NpgsqlCommand (that returns a 1x1 resultset) against the specified NpgsqlTransaction
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount", new NpgsqlParameter("@prodid", 24));
/// </remarks>
/// <param name="transaction">a valid NpgsqlTransaction</param>
/// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
/// <param name="commandText">the stored procedure name or T-Npgsql command</param>
/// <param name="commandParameters">an array of NpgsqlParamters used to execute the command</param>
/// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(NpgsqlTransaction transaction, CommandType commandType, string commandText, params NpgsqlParameter[] commandParameters)
{
//create a command and prepare it for execution
NpgsqlCommand cmd = new NpgsqlCommand();
PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters);
//execute the command & return the results
return cmd.ExecuteScalar();
}
/// <summary>
/// Execute a stored procedure via a NpgsqlCommand (that returns a 1x1 resultset) against the specified
/// NpgsqlTransaction using the provided parameter values. This method will query the database to discover the parameters for the
/// stored procedure (the first time each stored procedure is called), and assign the values based on parameter order.
/// </summary>
/// <remarks>
/// This method provides no access to output parameters or the stored procedure's return value parameter.
///
/// e.g.:
/// int orderCount = (int)ExecuteScalar(trans, "GetOrderCount", 24, 36);
/// </remarks>
/// <param name="transaction">a valid NpgsqlTransaction</param>
/// <param name="spName">the name of the stored prcedure</param>
/// <param name="parameterValues">an array of objects to be assigned as the input values of the stored procedure</param>
/// <returns>an object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(NpgsqlTransaction transaction, string spName, params object[] parameterValues)
{
//if we got parameter values, we need to figure out where they go
if ((parameterValues != null) && (parameterValues.Length > 0))
{
//pull the parameters for this stored procedure from the parameter cache (or discover them & populet the cache)
NpgsqlParameter[] commandParameters = NpgsqlHelperParameterCache.GetSpParameterSet(transaction.Connection.ConnectionString, spName);
//assign the provided values to these parameters based on parameter order
AssignParameterValues(commandParameters, parameterValues);
//call the overload that takes an array of NpgsqlParameters
return ExecuteScalar(transaction, CommandType.StoredProcedure, spName, commandParameters);
}
//otherwise we can just call the SP without params
else
{
return ExecuteScalar(transaction, CommandType.StoredProcedure, spName);
}
}
#endregion ExecuteScalar
}
/// <summary>
/// NpgsqlHelperParameterCache provides functions to leverage a static cache of procedure parameters, and the
/// ability to discover parameters for stored procedures at run-time.
/// </summary>
public sealed class NpgsqlHelperParameterCache
{
#region private methods, variables, and constructors
//Since this class provides only static methods, make the default constructor private to prevent
//instances from being created with "new NpgsqlHelperParameterCache()".
private NpgsqlHelperParameterCache() { }
private static Hashtable paramCache = Hashtable.Synchronized(new Hashtable());
/// <summary>
/// resolve at run-time the appropriate set of NpgsqlParameters for a stored procedure
/// </summary>
/// <param name="connectionString">a valid connection string for a NpgsqlConnection</param>
/// <param name="spName">the name of the stored prcedure</param>
/// <param name="includeReturnValueParameter">weather or not to onclude ther return value parameter</param>
/// <returns></returns>
private static NpgsqlParameter[] DiscoverSpParameterSet(string connectionString, string spName, bool includeReturnValueParameter)
{
using (NpgsqlConnection cn = new NpgsqlConnection(connectionString))
using (NpgsqlCommand cmd = new NpgsqlCommand(spName, cn))
{
cn.Open();
cmd.CommandType = CommandType.StoredProcedure;
NpgsqlCommandBuilder.DeriveParameters(cmd);
if (!includeReturnValueParameter)
{
if (ParameterDirection.ReturnValue == cmd.Parameters[0].Direction)
cmd.Parameters.RemoveAt(0);
}
NpgsqlParameter[] discoveredParameters = new NpgsqlParameter[cmd.Parameters.Count];
cmd.Parameters.CopyTo(discoveredParameters, 0);
return discoveredParameters;
}
}
//deep copy of cached NpgsqlParameter array
private static NpgsqlParameter[] CloneParameters(NpgsqlParameter[] originalParameters)
{
NpgsqlParameter[] clonedParameters = new NpgsqlParameter[originalParameters.Length];
for (int i = 0, j = originalParameters.Length; i < j; i++)
{
clonedParameters[i] = (NpgsqlParameter)((ICloneable)originalParameters[i]).Clone();
}
return clonedParameters;
}
#endregion private methods, variables, and constructors
#region caching functions
/// <summary>
/// add parameter array to the cache
/// </summary>
/// <param name="connectionString">a valid connection string for an NpgsqlConnection</param>
/// <param name="commandText">the stored procedure name or T-Npgsql command</param>
/// <param name="commandParameters">an array of NpgsqlParamters to be cached</param>
public static void CacheParameterSet(string connectionString, string commandText, params NpgsqlParameter[] commandParameters)
{
string hashKey = connectionString + ":" + commandText;
paramCache[hashKey] = commandParameters;
}
/// <summary>
/// retrieve a parameter array from the cache
/// </summary>
/// <param name="connectionString">a valid connection string for a NpgsqlConnection</param>
/// <param name="commandText">the stored procedure name or T-Npgsql command</param>
/// <returns>an array of NpgsqlParameters</returns>
public static NpgsqlParameter[] GetCachedParameterSet(string connectionString, string commandText)
{
string hashKey = connectionString + ":" + commandText;
NpgsqlParameter[] cachedParameters = (NpgsqlParameter[])paramCache[hashKey];
if (cachedParameters == null)
{
return null;
}
else
{
return CloneParameters(cachedParameters);
}
}
#endregion caching functions
#region Parameter Discovery Functions
/// <summary>
/// Retrieves the set of NpgsqlParameters appropriate for the stored procedure
/// </summary>
/// <remarks>
/// This method will query the database for this information, and then store it in a cache for future requests.
/// </remarks>
/// <param name="connectionString">a valid connection string for a NpgsqlConnection</param>
/// <param name="spName">the name of the stored prcedure</param>
/// <returns>an array of NpgsqlParameters</returns>
public static NpgsqlParameter[] GetSpParameterSet(string connectionString, string spName)
{
return GetSpParameterSet(connectionString, spName, true);
}
/// <summary>
/// Retrieves the set of NpgsqlParameters appropriate for the stored procedure
/// </summary>
/// <remarks>
/// This method will query the database for this information, and then store it in a cache for future requests.
/// </remarks>
/// <param name="connectionString">a valid connection string for an NpgsqlConnection</param>
/// <param name="spName">the name of the stored procedure</param>
/// <param name="includeReturnValueParameter">a bool value indicating weather the return value parameter should be included in the results</param>
/// <returns>an array of NpgsqlParameters</returns>
public static NpgsqlParameter[] GetSpParameterSet(string connectionString, string spName, bool includeReturnValueParameter)
{
string hashKey = connectionString + ":" + spName + (includeReturnValueParameter ? ":include ReturnValue Parameter" : "");
NpgsqlParameter[] cachedParameters;
cachedParameters = (NpgsqlParameter[])paramCache[hashKey];
if (cachedParameters == null)
{
cachedParameters = (NpgsqlParameter[])(paramCache[hashKey] = DiscoverSpParameterSet(connectionString, spName, includeReturnValueParameter));
}
return CloneParameters(cachedParameters);
}
#endregion Parameter Discovery Functions
}
}