OleDbConnection OleDbConnection OleDbConnection OleDbConnection Class

定义

表示到数据源的连接是打开的。Represents an open connection to a data source.

public ref class OleDbConnection sealed : System::Data::Common::DbConnection, ICloneable, IDisposable
public sealed class OleDbConnection : System.Data.Common.DbConnection, ICloneable, IDisposable
type OleDbConnection = class
    inherit DbConnection
    interface ICloneable
    interface IDbConnection
    interface IDisposable
Public NotInheritable Class OleDbConnection
Inherits DbConnection
Implements ICloneable, IDisposable
继承
实现

示例

下面的示例创建一个OleDbCommand和一个OleDbConnectionThe following example creates an OleDbCommand and an OleDbConnection. 打开并将设置ConnectionOleDbCommand的。 OleDbConnectionThe OleDbConnection is opened and set as the Connection for the OleDbCommand. 然后,该示例ExecuteNonQuery调用并关闭连接。The example then calls ExecuteNonQuery and closes the connection. 为实现此目的ExecuteNonQuery ,传递的是一个连接字符串和一个 SQL INSERT 语句的查询字符串。To accomplish this, ExecuteNonQuery is passed a connection string and a query string that is an SQL INSERT statement.

public void InsertRow(string connectionString, string insertSQL)
{
    using (OleDbConnection connection = new OleDbConnection(connectionString))
    {
        // The insertSQL string contains a SQL statement that
        // inserts a new row in the source table.
        OleDbCommand command = new OleDbCommand(insertSQL);

        // Set the Connection to the new OleDbConnection.
        command.Connection = connection;

        // Open the connection and execute the insert command.
        try
        {
            connection.Open();
            command.ExecuteNonQuery();
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }
        // The connection is automatically closed when the
        // code exits the using block.
    }
}
Public Sub InsertRow(ByVal connectionString As String, _
    ByVal insertSQL As String)

    Using connection As New OleDbConnection(connectionString)
        ' The insertSQL string contains a SQL statement that
        ' inserts a new row in the source table.
        Dim command As New OleDbCommand(insertSQL)

        ' Set the Connection to the new OleDbConnection.
        command.Connection = connection

        ' Open the connection and execute the insert command.
        Try
            connection.Open()
            command.ExecuteNonQuery()
        Catch ex As Exception
            Console.WriteLine(ex.Message)
        End Try
        ' The connection is automatically closed when the
        ' code exits the Using block.
    End Using
End Sub

注解

OleDbConnection对象表示与数据源的唯一连接。An OleDbConnection object represents a unique connection to a data source. 对于客户端/服务器数据库系统,它等效于到服务器的网络连接。With a client/server database system, it is equivalent to a network connection to the server. OleDbConnection对象的某些方法或属性可能不可用,具体取决于本机 OLE DB 提供程序支持的功能。Depending on the functionality supported by the native OLE DB provider, some methods or properties of an OleDbConnection object may not be available.

创建的OleDbConnection实例时,所有属性都将设置为其初始值。When you create an instance of OleDbConnection, all properties are set to their initial values. 有关这些值的列表,请参见OleDbConnection构造函数。For a list of these values, see the OleDbConnection constructor.

您可以在单个OleDbConnection上打开多个 DataReader。You can open more than one DataReader on a single OleDbConnection. 如果你使用的 OLE DB 提供程序在单个连接上不支持多个 DataReader,则访问接口将为每个连接隐式打开一个其他连接。If the OLE DB provider you use does not support more than one DataReader on a single connection, the provider implicitly opens an additional connection for each.

OleDbConnection如果超出范围,则它不会关闭。If the OleDbConnection goes out of scope, it is not closed. 因此,您必须通过Close调用或DisposeOleDbConnection或在Using语句中使用对象来显式关闭连接。Therefore, you must explicitly close the connection by calling Close or Dispose, or by using the OleDbConnection object within a Using statement.

备注

若要部署高性能应用程序,必须使用连接池。To deploy high-performance applications, you must use connection pooling. 使用 OLE DB 的 .NET Framework 数据提供程序时,不必启用连接池,因为提供程序会自动管理此。When you use the .NET Framework Data Provider for OLE DB, you do not have to enable connection pooling because the provider manages this automatically. 有关如何对用于 OLE DB 的 .NET Framework 数据提供程序使用连接池的详细信息,请参阅OLE DB、ODBC 和 Oracle 连接池For more information about how to use connection pooling with the .NET Framework Data Provider for OLE DB, see OLE DB, ODBC, and Oracle Connection Pooling.

如果OleDbException 执行的方法生成OleDbConnection了严重错误(例如 SQL Server,严重级别为20或更高) ,则可能已关闭。OleDbCommandIf a fatal OleDbException (for example, a SQL Server severity level of 20 or greater) is generated by the method executing an OleDbCommand, the OleDbConnection might be closed. 但是,用户可以重新打开连接并继续操作。However, the user can reopen the connection and continue.

创建OleDbConnection对象实例的应用程序可以通过设置声明性或命令性安全要求,要求所有直接和间接调用方具有对代码的足够权限。An application that creates an instance of the OleDbConnection object can require all direct and indirect callers to have sufficient permission to the code by setting declarative or imperative security demands. OleDbConnection使用OleDbPermission对象进行安全要求。OleDbConnection makes security demands using the OleDbPermission object. 用户可以使用OleDbPermissionAttribute对象验证其代码是否具有足够的权限。Users can verify that their code has sufficient permissions by using the OleDbPermissionAttribute object. 用户和管理员还可以使用caspol.exe (代码访问安全策略工具)在计算机、用户和企业级别修改安全策略。Users and administrators can also use the Caspol.exe (Code Access Security Policy Tool) to modify security policy at the computer, user, and enterprise levels. 有关更多信息,请参见 Code Access Security and ADO.NETFor more information, see Code Access Security and ADO.NET.

有关处理来自数据服务器的警告和信息性消息的详细信息,请参阅连接事件For more information about handling warning and informational messages from the data server, see Connection Events.

备注

OleDbConnection对象不支持设置或检索特定于 OLE DB 提供程序的动态属性。The OleDbConnection object does not support setting or retrieving dynamic properties specific to an OLE DB provider. 只支持可在 OLE DB 提供程序连接字符串中传递的属性。Only properties that can be passed in the connection string for the OLE DB provider are supported.

构造函数

OleDbConnection() OleDbConnection() OleDbConnection() OleDbConnection()

初始化 OleDbConnection 类的新实例。Initializes a new instance of the OleDbConnection class.

OleDbConnection(String) OleDbConnection(String) OleDbConnection(String) OleDbConnection(String)

使用指定的连接字符串初始化 OleDbConnection 类的新实例。Initializes a new instance of the OleDbConnection class with the specified connection string.

属性

CanRaiseEvents CanRaiseEvents CanRaiseEvents CanRaiseEvents

获取一个指示组件是否可以引发事件的值。Gets a value indicating whether the component can raise an event.

(Inherited from Component)
ConnectionString ConnectionString ConnectionString ConnectionString

获取或设置用于打数据库的字符串。Gets or sets the string used to open a database.

ConnectionTimeout ConnectionTimeout ConnectionTimeout ConnectionTimeout

获取终止尝试并生成错误之前在尝试建立连接时所等待的时间。Gets the time to wait while trying to establish a connection before terminating the attempt and generating an error.

Container Container Container Container

获取 IContainer,它包含 ComponentGets the IContainer that contains the Component.

(Inherited from Component)
Database Database Database Database

获取当前数据库的名称或打开连接后要使用的数据库的名称。Gets the name of the current database or the database to be used after a connection is opened.

DataSource DataSource DataSource DataSource

获取数据源的服务器名或文件名。Gets the server name or file name of the data source.

DesignMode DesignMode DesignMode DesignMode

获取一个值,用以指示 Component 当前是否处于设计模式。Gets a value that indicates whether the Component is currently in design mode.

(Inherited from Component)
Events Events Events Events

获取附加到此 Component 的事件处理程序的列表。Gets the list of event handlers that are attached to this Component.

(Inherited from Component)
Provider Provider Provider Provider

获取在连接字符串的“Provider = ”子句中指定的 OLE DB 提供程序的名称。Gets the name of the OLE DB provider specified in the "Provider= " clause of the connection string.

ServerVersion ServerVersion ServerVersion ServerVersion

获取一个包含客户端所连接到的服务器的版本的字符串。Gets a string that contains the version of the server to which the client is connected.

Site Site Site Site

获取或设置 ComponentISiteGets or sets the ISite of the Component.

(Inherited from Component)
State State State State

获取连接的当前状态。Gets the current state of the connection.

方法

BeginTransaction() BeginTransaction() BeginTransaction() BeginTransaction()

以当前的 IsolationLevel 值开始数据库事务。Starts a database transaction with the current IsolationLevel value.

BeginTransaction(IsolationLevel) BeginTransaction(IsolationLevel) BeginTransaction(IsolationLevel) BeginTransaction(IsolationLevel)

以指定的隔离级别启动数据库事务。Starts a database transaction with the specified isolation level.

ChangeDatabase(String) ChangeDatabase(String) ChangeDatabase(String) ChangeDatabase(String)

更改已打开的 OleDbConnection 的当前数据库。Changes the current database for an open OleDbConnection.

Close() Close() Close() Close()

关闭到数据源的连接。Closes the connection to the data source.

CreateCommand() CreateCommand() CreateCommand() CreateCommand()

创建并返回一个与该 OleDbCommand 关联的 OleDbConnection 对象。Creates and returns an OleDbCommand object associated with the OleDbConnection.

CreateObjRef(Type) CreateObjRef(Type) CreateObjRef(Type) CreateObjRef(Type)

创建一个对象,该对象包含生成用于与远程对象进行通信的代理所需的全部相关信息。Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.

(Inherited from MarshalByRefObject)
Dispose() Dispose() Dispose() Dispose()

释放由 Component 使用的所有资源。Releases all resources used by the Component.

(Inherited from Component)
Dispose(Boolean) Dispose(Boolean) Dispose(Boolean) Dispose(Boolean)

释放由 Component 占用的非托管资源,还可以另外再释放托管资源。Releases the unmanaged resources used by the Component and optionally releases the managed resources.

(Inherited from Component)
EnlistDistributedTransaction(ITransaction) EnlistDistributedTransaction(ITransaction) EnlistDistributedTransaction(ITransaction) EnlistDistributedTransaction(ITransaction)

在指定的事务中登记为分布式事务。Enlists in the specified transaction as a distributed transaction.

EnlistTransaction(Transaction) EnlistTransaction(Transaction) EnlistTransaction(Transaction) EnlistTransaction(Transaction)

在指定的事务中登记为分布式事务。Enlists in the specified transaction as a distributed transaction.

Equals(Object) Equals(Object) Equals(Object) Equals(Object)

确定指定的对象是否等于当前对象。Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetHashCode() GetHashCode() GetHashCode() GetHashCode()

作为默认哈希函数。Serves as the default hash function.

(Inherited from Object)
GetLifetimeService() GetLifetimeService() GetLifetimeService() GetLifetimeService()

检索控制此实例的生存期策略的当前生存期服务对象。Retrieves the current lifetime service object that controls the lifetime policy for this instance.

(Inherited from MarshalByRefObject)
GetOleDbSchemaTable(Guid, Object[]) GetOleDbSchemaTable(Guid, Object[]) GetOleDbSchemaTable(Guid, Object[]) GetOleDbSchemaTable(Guid, Object[])

应用了指定的限制之后,按照 GUID 的指示从数据源返回架构信息。Returns schema information from a data source as indicated by a GUID, and after it applies the specified restrictions.

GetSchema() GetSchema() GetSchema() GetSchema()

返回此 OleDbConnection 的数据源的架构信息。Returns schema information for the data source of this OleDbConnection.

GetSchema(String) GetSchema(String) GetSchema(String) GetSchema(String)

通过使用架构名称的指定字符串,返回此 OleDbConnection 的数据源的架构信息。Returns schema information for the data source of this OleDbConnection using the specified string for the schema name.

GetSchema(String, String[]) GetSchema(String, String[]) GetSchema(String, String[]) GetSchema(String, String[])

通过使用指定字符串作为架构名称,指定字符串数组作为限制值,返回此 OleDbConnection 的数据源的架构信息。Returns schema information for the data source of this OleDbConnection using the specified string for the schema name and the specified string array for the restriction values.

GetService(Type) GetService(Type) GetService(Type) GetService(Type)

返回一个对象,该对象表示由 Component 或它的 Container 提供的服务。Returns an object that represents a service provided by the Component or by its Container.

(Inherited from Component)
GetType() GetType() GetType() GetType()

获取当前实例的 TypeGets the Type of the current instance.

(Inherited from Object)
InitializeLifetimeService() InitializeLifetimeService() InitializeLifetimeService() InitializeLifetimeService()

获取生存期服务对象来控制此实例的生存期策略。Obtains a lifetime service object to control the lifetime policy for this instance.

(Inherited from MarshalByRefObject)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

创建当前 Object 的浅表副本。Creates a shallow copy of the current Object.

(Inherited from Object)
MemberwiseClone(Boolean) MemberwiseClone(Boolean) MemberwiseClone(Boolean) MemberwiseClone(Boolean)

创建当前 MarshalByRefObject 对象的浅表副本。Creates a shallow copy of the current MarshalByRefObject object.

(Inherited from MarshalByRefObject)
Open() Open() Open() Open()

使用由 ConnectionString 指定的属性设置打开一个数据库连接。Opens a database connection with the property settings specified by the ConnectionString.

ReleaseObjectPool() ReleaseObjectPool() ReleaseObjectPool() ReleaseObjectPool()

指示可在释放最后一个基础连接时释放 OleDbConnection 对象池。Indicates that the OleDbConnection object pool can be released when the last underlying connection is released.

ResetState() ResetState() ResetState() ResetState()

更新 State 对象的 OleDbConnection 属性。Updates the State property of the OleDbConnection object.

ToString() ToString() ToString() ToString()

返回包含 Component 的名称的 String(如果有)。Returns a String containing the name of the Component, if any. 不应重写此方法。This method should not be overridden.

(Inherited from Component)

事件

Disposed Disposed Disposed Disposed

当通过调用 Dispose() 方法释放组件时发生。Occurs when the component is disposed by a call to the Dispose() method.

(Inherited from Component)
InfoMessage InfoMessage InfoMessage InfoMessage

在提供程序发送警告或信息性消息时发生。Occurs when the provider sends a warning or an informational message.

StateChange StateChange StateChange StateChange

显式界面实现

ICloneable.Clone() ICloneable.Clone() ICloneable.Clone() ICloneable.Clone()

有关此成员的说明,请参见 Clone()For a description of this member, see Clone().

IDbConnection.BeginTransaction() IDbConnection.BeginTransaction() IDbConnection.BeginTransaction() IDbConnection.BeginTransaction()

开始一项数据库事务。Begins a database transaction.

IDbConnection.BeginTransaction(IsolationLevel) IDbConnection.BeginTransaction(IsolationLevel) IDbConnection.BeginTransaction(IsolationLevel) IDbConnection.BeginTransaction(IsolationLevel)

以指定的隔离级别启动数据库事务。Begins a database transaction with the specified isolation level.

IDbConnection.CreateCommand() IDbConnection.CreateCommand() IDbConnection.CreateCommand() IDbConnection.CreateCommand()

创建并返回与连接关联的命令对象。Creates and returns a command object associated with the connection.

适用于

另请参阅