Class NpgsqlCommand

Represents a SQL statement or function (stored procedure) to execute against a PostgreSQL database. This class cannot be inherited.

Inheritance

Object

MarshalByRefObject

Component

DbCommand

NpgsqlCommand

Implements

IDbCommand

IAsyncDisposable

ICloneable

IComponent

IDisposable

Inherited Members

DbCommand.ExecuteNonQueryAsync()

DbCommand.ExecuteReader()

DbCommand.ExecuteReaderAsync()

DbCommand.ExecuteReaderAsync(CommandBehavior)

DbCommand.ExecuteScalarAsync()

DbCommand.IDbCommand.CreateParameter()

DbCommand.IDbCommand.ExecuteReader()

DbCommand.IDbCommand.ExecuteReader(CommandBehavior)

DbCommand.DisposeAsync()

DbCommand.IDbCommand.Connection

DbCommand.IDbCommand.Parameters

DbCommand.IDbCommand.Transaction

Component.Dispose()

Component.GetService(Type)

Component.ToString()

Component.CanRaiseEvents

Component.Container

Component.DesignMode

Component.Events

Component.Site

Component.Disposed

MarshalByRefObject.GetLifetimeService()

MarshalByRefObject.InitializeLifetimeService()

MarshalByRefObject.MemberwiseClone(Boolean)

Object.Equals(Object)

Object.Equals(Object, Object)

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Object.ReferenceEquals(Object, Object)

Namespace: Npgsql

Assembly: Npgsql.dll

Syntax

public class NpgsqlCommand : DbCommand, IDbCommand, IAsyncDisposable, ICloneable, IComponent, IDisposable

Constructors

NpgsqlCommand()

Initializes a new instance of the NpgsqlCommand class.

Declaration

public NpgsqlCommand()

NpgsqlCommand(String, NpgsqlConnection, NpgsqlTransaction)

Initializes a new instance of the NpgsqlCommand class with the text of the query, a NpgsqlConnection, and the NpgsqlTransaction.

Declaration

public NpgsqlCommand(string cmdText, NpgsqlConnection connection, NpgsqlTransaction transaction)

Parameters

Type	Name	Description
String	cmdText	The text of the query.
NpgsqlConnection	connection	A NpgsqlConnection that represents the connection to a PostgreSQL server.
NpgsqlTransaction	transaction	The NpgsqlTransaction in which the NpgsqlCommand executes.

NpgsqlCommand(String, NpgsqlConnection)

Initializes a new instance of the NpgsqlCommand class with the text of the query and a NpgsqlConnection.

Declaration

public NpgsqlCommand(string cmdText, NpgsqlConnection connection)

Parameters

Type	Name	Description
String	cmdText	The text of the query.
NpgsqlConnection	connection	A NpgsqlConnection that represents the connection to a PostgreSQL server.

NpgsqlCommand(String)

Initializes a new instance of the NpgsqlCommand class with the text of the query.

Declaration

public NpgsqlCommand(string cmdText)

Parameters

Type	Name	Description
String	cmdText	The text of the query.

Properties

AllResultTypesAreUnknown

Marks all of the query's result columns as either known or unknown. Unknown result columns are requested from PostgreSQL in text format, and Npgsql makes no attempt to parse them. They will be accessible as strings only.

Declaration

public bool AllResultTypesAreUnknown { get; set; }

Property Value

Type	Description
Boolean

CommandText

Gets or sets the SQL statement or function (stored procedure) to execute at the data source.

Declaration

public override string CommandText { get; set; }

Property Value

Type	Description
String	The SQL statement or function (stored procedure) to execute. The default is an empty string.

Overrides

DbCommand.CommandText

CommandTimeout

Gets or sets the wait time (in seconds) before terminating the attempt to execute a command and generating an error.

Declaration

public override int CommandTimeout { get; set; }

Property Value

Type	Description
Int32	The time (in seconds) to wait for the command to execute. The default value is 30 seconds.

Overrides

DbCommand.CommandTimeout

CommandType

Gets or sets a value indicating how the CommandText property is to be interpreted.

Declaration

public override CommandType CommandType { get; set; }

Property Value

Type	Description
CommandType	One of the CommandType values. The default is Text.

Overrides

DbCommand.CommandType

Connection

Gets or sets the NpgsqlConnection used by this instance of the NpgsqlCommand.

Declaration

public NpgsqlConnection Connection { get; set; }

Property Value

Type	Description
NpgsqlConnection	The connection to a data source. The default value is null.

DbConnection

DB connection.

Declaration

protected override DbConnection DbConnection { get; set; }

Property Value

Type	Description
DbConnection

Overrides

DbCommand.DbConnection

DbParameterCollection

DB parameter collection.

Declaration

protected override DbParameterCollection DbParameterCollection { get; }

Property Value

Type	Description
DbParameterCollection

Overrides

DbCommand.DbParameterCollection

DbTransaction

DB transaction.

Declaration

protected override DbTransaction DbTransaction { get; set; }

Property Value

Type	Description
DbTransaction

Overrides

DbCommand.DbTransaction

DesignTimeVisible

Design time visible.

Declaration

public override bool DesignTimeVisible { get; set; }

Property Value

Type	Description
Boolean

Overrides

DbCommand.DesignTimeVisible

IsPrepared

Returns whether this query will execute as a prepared (compiled) query.

Declaration

public bool IsPrepared { get; }

Property Value

Type	Description
Boolean

Parameters

Gets the NpgsqlParameterCollection.

Declaration

public NpgsqlParameterCollection Parameters { get; }

Property Value

Type	Description
NpgsqlParameterCollection	The parameters of the SQL statement or function (stored procedure). The default is an empty collection.

Statements

Returns details about each statement that this command has executed. Is only populated when an Execute* method is called.

Declaration

[Obsolete("Use the new DbBatch API")]
public IReadOnlyList<NpgsqlBatchCommand> Statements { get; }

Property Value

Type	Description
IReadOnlyList<NpgsqlBatchCommand>

Transaction

This property is ignored by Npgsql. PostgreSQL only supports a single transaction at a given time on a given connection, and all commands implicitly run inside the current transaction started via BeginTransaction()

Declaration

public NpgsqlTransaction Transaction { get; set; }

Property Value

Type	Description
NpgsqlTransaction

UnknownResultTypeList

Marks the query's result columns as known or unknown, on a column-by-column basis. Unknown result columns are requested from PostgreSQL in text format, and Npgsql makes no attempt to parse them. They will be accessible as strings only.

Declaration

public bool[] UnknownResultTypeList { get; set; }

Property Value

Type	Description
Boolean[]

Remarks

If the query includes several queries (e.g. SELECT 1; SELECT 2), this will only apply to the first one. The rest of the queries will be fetched and parsed as usual.

The array size must correspond exactly to the number of result columns the query returns, or an error will be raised.

UpdatedRowSource

Gets or sets how command results are applied to the DataRow when used by the DbDataAdapter.Update(DataSet) method.

Declaration

public override UpdateRowSource UpdatedRowSource { get; set; }

Property Value

Type	Description
UpdateRowSource	One of the UpdateRowSource values.

Overrides

DbCommand.UpdatedRowSource

Methods

Cancel()

Attempts to cancel the execution of an NpgsqlCommand.

Declaration

public override void Cancel()

Overrides

DbCommand.Cancel()

Remarks

As per the specs, no exception will be thrown by this method in case of failure.

Clone()

Create a new command based on this one.

Declaration

public virtual NpgsqlCommand Clone()

Returns

Type	Description
NpgsqlCommand	A new NpgsqlCommand object.

CreateDbParameter()

Creates a new instance of an DbParameter object.

Declaration

protected override DbParameter CreateDbParameter()

Returns

Type	Description
DbParameter	A DbParameter object.

Overrides

DbCommand.CreateDbParameter()

CreateParameter()

Creates a new instance of a NpgsqlParameter object.

Declaration

public NpgsqlParameter CreateParameter()

Returns

Type	Description
NpgsqlParameter	An NpgsqlParameter object.

Dispose(Boolean)

Represents a SQL statement or function (stored procedure) to execute against a PostgreSQL database. This class cannot be inherited.

Declaration

protected override void Dispose(bool disposing)

Parameters

Type	Name	Description
Boolean	disposing

Overrides

Component.Dispose(Boolean)

ExecuteDbDataReader(CommandBehavior)

Executes the command text against the connection.

Declaration

protected override DbDataReader ExecuteDbDataReader(CommandBehavior behavior)

Parameters

Type	Name	Description
CommandBehavior	behavior

Returns

Type	Description
DbDataReader	A task representing the operation.

Overrides

DbCommand.ExecuteDbDataReader(CommandBehavior)

ExecuteDbDataReaderAsync(CommandBehavior, CancellationToken)

Executes the command text against the connection.

Declaration

protected override async Task<DbDataReader> ExecuteDbDataReaderAsync(CommandBehavior behavior, CancellationToken cancellationToken)

Parameters

Type	Name	Description
CommandBehavior	behavior	An instance of CommandBehavior.
CancellationToken	cancellationToken	An optional token to cancel the asynchronous operation. The default value is None.

Returns

Type	Description
Task<DbDataReader>	A task representing the asynchronous operation.

Overrides

DbCommand.ExecuteDbDataReaderAsync(CommandBehavior, CancellationToken)

ExecuteNonQuery()

Executes a SQL statement against the connection and returns the number of rows affected.

Declaration

public override int ExecuteNonQuery()

Returns

Type	Description
Int32	The number of rows affected if known; -1 otherwise.

Overrides

DbCommand.ExecuteNonQuery()

ExecuteNonQueryAsync(CancellationToken)

Asynchronous version of ExecuteNonQuery()

Declaration

public override Task<int> ExecuteNonQueryAsync(CancellationToken cancellationToken)

Parameters

Type	Name	Description
CancellationToken	cancellationToken	An optional token to cancel the asynchronous operation. The default value is None.

Returns

Type	Description
Task<Int32>	A task representing the asynchronous operation, with the number of rows affected if known; -1 otherwise.

Overrides

DbCommand.ExecuteNonQueryAsync(CancellationToken)

ExecuteReader(CommandBehavior)

Executes the CommandText against the Connection and returns a NpgsqlDataReader.

Declaration

public NpgsqlDataReader ExecuteReader(CommandBehavior behavior = CommandBehavior.Default)

Parameters

Type	Name	Description
CommandBehavior	behavior	One of the enumeration values that specifies the command behavior.

Returns

Type	Description
NpgsqlDataReader	A task representing the operation.

ExecuteReaderAsync(CommandBehavior, CancellationToken)

An asynchronous version of ExecuteReader(CommandBehavior), which executes the CommandText against the Connection and returns a NpgsqlDataReader.

Declaration

public Task<NpgsqlDataReader> ExecuteReaderAsync(CommandBehavior behavior, CancellationToken cancellationToken = default(CancellationToken))

Parameters

Type	Name	Description
CommandBehavior	behavior	One of the enumeration values that specifies the command behavior.
CancellationToken	cancellationToken	An optional token to cancel the asynchronous operation. The default value is None.

Returns

Type	Description
Task<NpgsqlDataReader>	A task representing the asynchronous operation.

ExecuteReaderAsync(CancellationToken)

An asynchronous version of ExecuteReader(CommandBehavior), which executes the CommandText against the Connection and returns a NpgsqlDataReader.

Declaration

public Task<NpgsqlDataReader> ExecuteReaderAsync(CancellationToken cancellationToken = default(CancellationToken))

Parameters

Type	Name	Description
CancellationToken	cancellationToken	An optional token to cancel the asynchronous operation. The default value is None.

Returns

Type	Description
Task<NpgsqlDataReader>	A task representing the asynchronous operation.

ExecuteScalar()

Executes the query, and returns the first column of the first row in the result set returned by the query. Extra columns or rows are ignored.

Declaration

public override object ExecuteScalar()

Returns

Type	Description
Object	The first column of the first row in the result set, or a null reference if the result set is empty.

Overrides

DbCommand.ExecuteScalar()

ExecuteScalarAsync(CancellationToken)

Asynchronous version of ExecuteScalar()

Declaration

public override Task<object> ExecuteScalarAsync(CancellationToken cancellationToken)

Parameters

Type	Name	Description
CancellationToken	cancellationToken	An optional token to cancel the asynchronous operation. The default value is None.

Returns

Type	Description
Task<Object>	A task representing the asynchronous operation, with the first column of the first row in the result set, or a null reference if the result set is empty.

Overrides

DbCommand.ExecuteScalarAsync(CancellationToken)

Prepare()

Creates a server-side prepared statement on the PostgreSQL server. This will make repeated future executions of this command much faster.

Declaration

public override void Prepare()

Overrides

DbCommand.Prepare()

PrepareAsync(CancellationToken)

Creates a server-side prepared statement on the PostgreSQL server. This will make repeated future executions of this command much faster.

Declaration

public override Task PrepareAsync(CancellationToken cancellationToken = default(CancellationToken))

Parameters

Type	Name	Description
CancellationToken	cancellationToken	An optional token to cancel the asynchronous operation. The default value is None.

Returns

Type	Description
Task

Overrides

DbCommand.PrepareAsync(CancellationToken)

Unprepare()

Unprepares a command, closing server-side statements associated with it. Note that this only affects commands explicitly prepared with Prepare(), not automatically prepared statements.

Declaration

public void Unprepare()

UnprepareAsync(CancellationToken)

Unprepares a command, closing server-side statements associated with it. Note that this only affects commands explicitly prepared with Prepare(), not automatically prepared statements.

Declaration

public Task UnprepareAsync(CancellationToken cancellationToken = default(CancellationToken))

Parameters

Type	Name	Description
CancellationToken	cancellationToken	An optional token to cancel the asynchronous operation. The default value is None.

Returns

Type	Description
Task

Explicit Interface Implementations

IComponent.Disposed

Represents a SQL statement or function (stored procedure) to execute against a PostgreSQL database. This class cannot be inherited.

Declaration

event EventHandler IComponent.Disposed

Returns

Type	Description
EventHandler

ICloneable.Clone()

Create a new command based on this one.

Declaration

object ICloneable.Clone()

Returns

Type	Description
Object	A new NpgsqlCommand object.

Implements

System.Data.IDbCommand

System.IAsyncDisposable

System.ICloneable

System.ComponentModel.IComponent

System.IDisposable