C # operate the ACCESS database (create and modify the structure)

ToProgramAccess control, not data, but the table structure of the Access database. The field is required.

Therefore, you must first reference it in the solution as follows:
Solution resource manager --> reference --> (right-click) Add reference --> com -->Microsoft ADO Ext. 2.8 for DDL and security 

 

Note:

When an Access database is created, a connection is automatically created. To release the. LDB file, the connection must be closed. This connection is from the ADODB class, so many people have never been able to find a way to release the connection.

The method is as follows: Reference --> (right-click) Add reference --> com -->Microsoft ActiveX Data Objects 2.8 Library

 

With these two COM components, you can start a series of operations...

 

1. Create an Access database

String Dbname =   " E: \ temp \\ "   + Datetime. Now. millisecond. tostring () +   " . MDB " ; // Note that the extension must be MDB; otherwise, the table cannot be inserted.
ADOX. catalogclass cat =   New ADOX. catalogclass ();
Cat. Create ( " Provider = Microsoft. Jet. oledb.4.0; Data Source = "   + Dbname +   " ; " );

II.Create a table

ADOX. tableclass TBL =   New ADOX. tableclass ();
TBL. parentcatalog = CAT;
TBL. Name =   " Mytable " ;

 

III.Add an Automatically increasing field

ADOX. columnclass col =   New ADOX. columnclass ();
Col. parentcatalog = CAT;
Col. Type = ADOX. datatypeenum. adinteger; // The field type must be set first.
Col. Name =   " ID " ;
Col. properties [ " Jet oledb: Allow Zero Length " ]. Value =   False ;
Col. properties [ " Autoincrement " ]. Value =   True ;
TBL. Columns. append (COL, ADOX. datatypeenum. adinteger, 0 );

 

4.Add a text field

ADOX. columnclass col2 =   New ADOX. columnclass ();
Col2.parentcatalog = CAT;
Col2.name =   " Description " ;
Col2.properties [ " Jet oledb: Allow Zero Length " ]. Value =   False ;
TBL. Columns. append (col2, ADOX. datatypeenum. advarchar, 25 );

The following sentence is very important:

Cat. Tables. append (TBL ); // Add tables to the database (very important)

5. Open and modify the ACCESS database

ADODB. Connection Conn =   New ADODB. Connection (); // ADO connection object
Conn. Open ( " Provider = Microsoft. Jet. oledb.4.0; Data Source = InterOP. Portal. dll " , "" , "" , 0 );
ADOX. catalogclass Cat =   New ADOX. catalogclass ();
Cat. activeconnection = Conn; // Set the active connection object

The following sentence is very important: (creation and modification are required)

// Convert to ADO connection and close
(Cat. activeconnection As ADODB. Connection). Close ();
Cat. activeconnection =   Null ;
Cat =   Null ;