1. The question was raised
When designing small and medium Web applications, you can choose the Microsoft Accesss as the database. Frequent additions and deletions are made during the use of the database. In fact, Microsoft Access does not effectively release allocated but deleted object space, which means that even if you delete an object, the object still occupies the space of the database, making the database bigger and larger. Not only occupy unnecessary space, but also reduce the efficiency of the database. Especially in the virtual site of the problem is particularly prominent. Therefore, compressing the Access database is of practical significance.
Although the Access database itself has the "Compress and Repair Database" feature (tool è database utility è compression and repair database). However, it is inconvenient for the general user to operate. Usually the ACCESSS database is placed on the virtual host, need to download it down "compression repair" and then pass up a waste of time, so it is best to compress the database online.
2. On-Line compression database implementation
2.1. Add Reference
Add a reference under the solution for the vs.net environment. The methods are as follows: Items → add references → tabs → browse (C:/Program files/comm files/system/ado/msjro.dll).
2.2. Create a Web application form
Place a button on the Web Form (database.aspx):
Copy Code code as follows:
<asp:button id= "compactbtn" runat= "server" text= "compressed Database" onclick= "Compactbtn_click"/>
Add a Label control again:
<asp:label id= "Msglabel" runat= "Server" ></asp:Label>
2.3. Add a reference in the Code state
Copy Code code as follows:
Using System;
Using System.IO;
Using JRO;
2.4. Add code
Copy Code code as follows:
Compressing a database
protected void Compactbtn_click (object sender, EventArgs e)
{
String DbPath1, DbPath2, DbConn1, DbConn2;
DbPath1 = Server.MapPath (".. /app_data/database.mdb ");//Original database path
DbPath2 = Server.MapPath (".. /app_data/database2.mdb ");//Compressed database path
DBCONN1 = "Provider=Microsoft.Jet.OLEDB.4.0;Data source=" + DbPath1;
DBCONN2 = "Provider=Microsoft.Jet.OLEDB.4.0;Data source=" + DbPath2;
Try
{
JetEngine databaseengin = new JetEngine ();
Databaseengin.compactdatabase (DBCONN1, DBCONN2);//Compression
File.Copy (DbPath2, DbPath1, true);//compress the database to overwrite the original database
File.delete (DbPath2);//Delete compressed database
Msglabel.text = "Database compression successful!";
}
Catch
{
Msglabel.text = "Database compression failed, please try again!";
}
}
3. Backing Up the database
3.1. Create a Web application form
Place a button on the Web Form (database2.aspx):
Copy Code code as follows:
<asp:button id= "backupbtn" runat= "Server" text= "Backup Database" onclick= "Backupbtn_click"/>
Add a Label control again:
<asp:label id= "Msglabel" runat= "Server" ></asp:Label>
3.2. Add a reference in the Code state
Copy Code code as follows:
Using System;
Using System.IO;
3.3. Add code
Copy Code code as follows:
Backing up a database
protected void Backupbtn_click (object sender, EventArgs e)
{
String DbPath1, DbPath2, dbname4dbpath2;
Dbname4dbpath2 = DateTime.Now.ToString (). Replace (":", ".");
DbPath1 = Server.MapPath (".. /app_data/database.mdb ");
DbPath2 = Server.MapPath (".. /app_data/"+ dbname4dbpath2 +". mdb ");
Try
{
File.Copy (DbPath1, DbPath2, true);
Msglabel.text = "Database backup succeeded to" + Dbname4dbpath2 + ". mdb!";
}
Catch
{
Msglabel.text = "Database backup failed, please try again!";
Msglabel.cssclass = "Redcolor";
}
}
4. Summary
Compression allows Microsoft Access to truly release the extra space it occupies, minimizing the database and ensuring it runs most efficiently. Therefore, during the design process, it is important not to overlook the importance of compressing Microsoft Access.
It is recommended that the database be backed up before compression.
