How to create an ADO.NET Connection object
This article introduces the knowledge of "how to create ADO.NET Connection objects". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!
By default, vc++ does not support ado objects. If you want to use the ado object in your program, you need to import the ado library file into the project using the # import command, as follows:
# import "c:\ Program Files\ Common Files\ System\ ado\ msado15.dll" no_namespace rename ("EOF", "adoEOF") rename ("BOF", "adoBOF")
The parameter no_namespace indicates a namespace that does not apply to ado. To avoid constant name conflicts, rename EOF to ADOBOF and BOF to ADOBOF. The ADO library contains three basic interfaces. That is, the _ ConnectPtr,_CommandPtr,_RecordSetPtr interface. They correspond to Connection objects, Command objects and RecordSet objects, respectively.
ADO.NET Connection object
The ADO.NET Connection object represents the connection to the data source. When accessing the database, first create an ADO.NET Connection object and use it to establish a connection to the database. You usually need to define a VConnection object in the header file.
_ ConnnetionPtr m_pConnection
The method to create a Connection object is as follows:
M_pConnection.CreateInstance ("ADODB.Connection")
ConnectionString attribute
ConnectionString= connection-> ConnectionString= "connection"
The time it takes for ConnectionTimeout to execute the command before terminating the attempt and generating an error, the default is 30sdepartment Mode, which specifies the permission of the Connection object to modify data. State returns the status of the Connection property, and the Open method is used to open a connection to the data source. Connection.Open (ConnectionString,UserId,Password,Options), the Close method (closes the connection to the database).
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