GAMBAS-BOOK 3.19.5

The class represents an (existing) database. All properties can only be read.

The Database class has three properties:

Table 22.4.4.1.1 : Properties of the Database class

System databases are used to operate a DB server (PostgreSQL, MySQL) or when using the DB library in SQLite. The database `mysql ` is used in MySQL, for example, to manage all log system tables.

The Database.Delete( ) method deletes a database.

The following source code snippet shows the use of all properties and the single method of the Database class:

    Dim hConnection As Connection
    Dim hDataBase As Database
    Dim sMessage As String
 
    For Each hDataBase In DBCS.DBConnection.Databases
 
      hConnection = hDataBase.Connection
 
      Print "Connection Host: "; hConnection.Host
      Print "DBName: "; hDataBase.Name 
      If hDataBase.System Then 
         Print "The database is a system DB"
      Else
         Print "The database is not a system DB"
      Endif
 
'-- Attention: The following instructions require attention!
'-- When a database is deleted, all tables with the data they contain are also deleted!
'-- Be sure to create a (complete) database backup (dump) beforehand.
 
      If hDataBase.Name = "contacts.sqlite" Then
         sMessage = "<center><h4><font color='red'>Achtung!<br>Should the database '"
         sMessage &= hDataBase.Name
         sMessage &= "' be completely deleted?</font color='red'></center></h3>"
         If Message.Question(sMessage, "Yes", "No - no way!") = 1 Then
            hDBDataBase.Delete()
         Endif
      Endif
 
    Next

The following output is produced in the console of the IDE. A delete query is then generated:

Connection Host: /home/hans/.local/share/gambasbook/dbplayground/data/databases
DBName: contacts.sqlite
The database is not a system DB

Figure 22.4.4.3.1: Query to delete a selected database