How to use c # To operate ACCESS databases

How to use c # To operate ACCESS databases: Microsoft ACCESS is not available at hand, and how to create a database is still simple. first, reference C: ProgramFilesCommonFilesSystemadomsadox. dll, which contains the ADOX namespace; then reference C: ProgramFilesCommonFilesSystemadomsjro. dll, which contains the JRO namespace SxS

How to use c # To operate ACCESS databases: Microsoft Access is not available at hand, and how to create a database is still simple. first, reference C: Program FilesCommon FilesSystemadomsadox. dll, which contains the ADOX namespace. Then reference C: Program FilesCommon FilesSystemadomsjro. dll, which contains the JRO namespace SxS

How to use c # To operate ACCESS databases:

There is no Microsoft Access at hand. It is still easy to create a database.

Reference C: Program FilesCommon FilesSystemadomsadox. dll, which contains the ADOX namespace;

Then reference C: Program FilesCommon FilesSystemadomsjro. dll, which contains the JRO namespace

Tips for SxS: for example, if the dll Import fails, manually import the com component as a. net Component and use vs.net to import it.

Using System;

Using System. IO;

Using ADOX; // The namespace contains the class (method) for creating ACCESS -- Solution ==> reference ==> add reference ==> find. dll

Using JRO; // The namespace contains the class (method) for compressing ACCESS)

Public class Access

...{

/** // Create an ACCESS database based on the specified file name

/// MdbPath: the absolute ACCESS path of the file to be created

Public void Create (string mdbPath)

...{

If (File. Exists (mdbPath) // check whether the database already Exists

...{

Throw new Exception ("the target database already exists and cannot be created ");

}

// You can add a password so that the created database can be opened only after the password is entered.

MdbPath = "Provider = Microsoft. Jet. OLEDB.4.0; Data Source =" + mdbPath;

// Create an instance of the CatalogClass object,

ADOX. CatalogClass cat = new ADOX. CatalogClass ();

// Use the Create method of the CatalogClass object to Create an ACCESS database

Cat. Create (mdbPath );

}

/*** // Compress and fix the ACCESS database. The mdbPath is the absolute path of the database.

Public void Compact (string mdbPath)

...{

If (! File. Exists (mdbPath) // check whether the database already Exists

...{

Throw new Exception ("the target database does not exist and cannot be compressed ");

}

// Declare the temporary database name

String temp = DateTime. Now. Year. ToString ();

Temp + = DateTime. Now. Month. ToString ();

Temp + = DateTime. Now. Day. ToString ();

Temp + = DateTime. Now. Hour. ToString ();

Temp + = DateTime. Now. Minute. ToString ();

Temp + = DateTime. Now. Second. ToString () + ". bak ";

Temp = mdbPath. Substring (0, mdbPath. LastIndexOf ("") + 1) + temp;

// Define the connection string of the temporary database

Temp2 = "Provider = Microsoft. Jet. OLEDB.4.0; Data Source =" + temp;

// Define the connection string of the target database

MdbPath2 = "Provider = Microsoft. Jet. OLEDB.4.0; Data Source =" + mdbPath;

// Create an instance of the JetEngineClass object

JRO. JetEngineClass jt = new JRO. JetEngineClass ();

// Use the CompactDatabase method of the JetEngineClass object to compress and restore the database

Jt. CompactDatabase (mdbPath2, temp2 );

// Copy the temporary database to the target database (overwrite)

File. Copy (temp, mdbPath, true );

// Delete the temporary database

File. Delete (temp );

}/** // Back up the database, mdb1, absolute path of the source database, and mdb2: absolute path of the target database

Public void Backup (string mdb1, string mdb2)

...{

If (! File. Exists (mdb1 ))

...{

Throw new Exception ("the source database does not exist ");

}

Try

...{

File. Copy (mdb1, mdb2, true );

}

Catch (IOException ixp)

...{

Throw new Exception (ixp. ToString ());

}

}

/** // Restore the database. mdb1 indicates the absolute path of the backup database, and mdb2 indicates the absolute path of the current database.

Public void Recover (string mdb1, string mdb2)

...{

If (! File. Exists (mdb1 ))

...{

Throw new Exception ("the backup database does not exist ");

}

Try

...{

File. Copy (mdb1, mdb2, true );

}

Catch (IOException ixp)

...{

Throw new Exception (ixp. ToString ());

}

}

}

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In BETA2 ,. NET provides the following NAMESPACE:

System. Data Namespace

System. Data. OleDb (it is different from BETA1, so it is definitely not possible to run the program in BETA1 to BETA2)

If I want to clarify these things, I don't think I can do it, so I want to use some specific programs to demonstrate the most basic database operations (SELECT, UPDATE, DELETE, INSERT, etc, other things need to be learned by friends!

To operate a database, you must first open the database. The following uses an ACCESS database as an example to illustrate how to open a database connection! Here we need to use: System. Data. OleDb. OleDbConnection class! (If you operate SQL databases, we 'd better use the System. Data. SqlClient. SqlConnection class)

I will first write my own program:

Using System. Data

Using System. Data. OleDb

Public OleDbConnection getConn ()

{

String connstr = "Provider = Microsoft. Jet. OLEDB.4.0; Data Source = F: webnotesbookclassleavenotes. mdb ";

OleDbConnection tempconn = new OleDbConnection (connstr );

Return (tempconn );

}

I believe that anyone who has used ADO can understand it! First, we define a variable of the String type, which stores the connection String that we connect to the database, and then define a System. data. oleDb. oleDbConnection type object, instantiate it, and finally return this object! It should be noted that I didn't put the statement: tempconn. Open (); into this function. The reason is that I will explain it later. Here I just want to remind you!

Through the above function, we have obtained a Connection object similar to the Connection object in ADO! The following is the specific database operation!

Before specific operations, I think it is necessary to first understand the following two classes:

System. Data. OleDb. OleDbDataAdapter

System. Data. OleDb. OleDbDataReader

System. Data. OleDb. OleDbDataAdapter: You can directly contact DataSet and operate the Data source. It is more powerful and consumes System resources!