Quick Start

The full E-Maj installation process is detailed later. However, the following commands provide a quick way to install and use E-Maj on Linux.

Install Software

If the pgxn client is installed, use this single command:

pgxn install emaj --sudo

Otherwise, follow these steps:

wget https://api.pgxn.org/dist/e-maj/<version>/e-maj-<version>.zip
unzip e-maj-<version>.zip
cd e-maj-<version>/
sudo make install

For more details or troubleshooting, refer to Install the E-Maj Software.

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Create the Extension

To install the emaj extension in a database:

1. Connect to the target database as a SUPERUSER and run:

   CREATE EXTENSION emaj CASCADE;
   

2. Grant E-Maj administration privileges to a specific role:

   GRANT emaj_adm TO <role>;
   

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Use the Extension

Connect to the database using the role with E-Maj administration rights.

1. Create a table group (here, a ROLLBACKABLE group):

   SELECT emaj.emaj_create_group('my_group', true);
   

2. Add tables and sequences to the group.

   For example, to add a single table:

   SELECT emaj.emaj_assign_table('my_schema', 'my_table', 'my_group');
   

   To add all tables and sequences from a schema:

   SELECT emaj.emaj_assign_tables('my_schema', '.*', '', 'my_group');
   SELECT emaj.emaj_assign_sequences('my_schema', '.*', '', 'my_group');
   

   Note

   Only tables having a PRIMARY KEY can be assigned to a ROLLBACKABLE group.

3. Typical workflow to log updates and roll back.

   Start the group and log updates:

   SELECT emaj.emaj_start_group('my_group', 'Mark-1');
   
   Perform database updates (*INSERT*/*UPDATE*/*DELETE*).
   

   Set intermediate marks:

   SELECT emaj.emaj_set_mark_group('my_group', 'Mark-2');
   
   Perform database updates (*INSERT*/*UPDATE*/*DELETE*).
   
   SELECT emaj.emaj_set_mark_group('my_group', 'Mark-3');
   
   Perform database updates (*INSERT*/*UPDATE*/*DELETE*).
   

   Roll back to a previous mark:

   SELECT emaj.emaj_rollback_group('my_group', 'Mark-2');
   

   Stop recording and drop the table group:

   SELECT emaj.emaj_stop_group('my_group');
   SELECT emaj.emaj_drop_group('my_group');
   

For more details, see the description of main functions.

Additionally, you can install and use the Emaj_web client for a graphical interface.