package AdaBase.Logger.Facility is
   type TAction is (attach, detach);
   type TLogger is (file, screen);
end AdaBase.Logger.Facility;

AdaBase.Driver.Base.[DB].command_standard_logger (device : TLogger; action : TAction)

There are three types of loggers (mechanisms uses to log AdaBase activity) and it is possible to use one instance of all three types simultaneously. The first two types are considered "standard" and they write to screen (stdout) and a file. This procedure handles the activation and deactivation of these standard loggers. The third type is "custom" which uses a dedicated set of attach and detach functions to operate.

To activate a standard logger, set the "action" argument to "attach". To deactivate an active logger, execute the procedure again with "action" set to "detach". Attempting to activate an active logger or deactivate an inactive logger will result in thrown exception. The device argument must be set to either "screen" or "file". If the log filename is not defined, the log will be written to the /tmp/adabase.log file.

AdaBase.Driver.Base.[DB].set_logger_filename (filename : String)

This procedure is used to define the location of the standard log file. The file will be created if necessary, and it will be appended if it already exists.

with AdaBase;
with Connect;
with Ada.Text_IO;
with AdaBase.Logger.Facility;

procedure Fruit3 is

   package CON renames Connect;
   package TIO renames Ada.Text_IO;
   package ALF renames AdaBase.Logger.Facility;

   numrows : AdaBase.Affected_Rows;

   log : constant String := "/tmp/fruit3.test.log";
   cmd : constant String := "DELETE FROM fruits WHERE color = 'red'";


   CON.DR.command_standard_logger (device => ALF.file, action => ALF.attach);
   CON.DR.set_logger_filename (filename => log);
   TIO.Put_Line ("The " & log & " has been attached.");


   numrows := CON.DR.execute (sql => cmd);
   TIO.Put_Line ("SQL: " & cmd);
   TIO.Put_Line ("Result: Deleted" & numrows'Img & " rows");

   CON.DR.command_standard_logger (device => ALF.file, action => ALF.detach);
   TIO.Put_Line ("The " & log & " has been deattached.");

   numrows := CON.DR.execute (sql => cmd);
   TIO.Put_Line ("Second execution:");
   TIO.Put_Line ("Result: Deleted" & numrows'Img & " rows");

   CON.DR.command_standard_logger (device => ALF.file, action => ALF.attach);
   TIO.Put_Line ("The " & log & " has been attached.");


end Fruit3;

Example code: testcases/fruit3/fruit3.adb

The /tmp/fruit3.test.log has been attached.
SQL: DELETE FROM fruits WHERE color = 'red'
Result: Deleted 5 rows
The /tmp/fruit3.test.log has been deattached.
Second execution:
Result: Deleted 0 rows
The /tmp/fruit3.test.log has been attached.

Output using any driver

2016-04-24 11:05:04    mysql :       Connect : Connection to adabase_examples database succeeded.
2016-04-24 11:05:04    mysql :       Execute : DELETE FROM fruits WHERE color = 'red'
2016-04-24 11:05:04    mysql :    Disconnect : Disconnect From database

Contents of /tmp/fruit3.test.log (MySQL driver)

See drop table query and compression settings [DS] for other examples using the standard screen logger.

[DB] is "MySQL.MySQL_Driver", "PostgreSQL.PostgreSQL_Driver", or "SQLite.SQLite_Driver"

See Also