One way to accept only one active session in a MySQL table is by using a flag column in the table to indicate the active session. Here's a step-by-step approach to achieving this:
- Add a flag column to your table to track the active session. For example, you can add a column named "active" with a Boolean data type.
ALTER TABLE your_table ADD active BOOLEAN DEFAULT FALSE;
- Whenever a new session needs to be started, you can update the flag column of the corresponding row to mark it as active. To do this, you can execute an UPDATE statement to set the "active" column to true for the desired row.
UPDATE your_table SET active = TRUE WHERE session_id = 'desired_session_id';
Ensure that you replace "your_table" with the actual table name and "desired_session_id" with the session id you want to mark as active.
- Before starting a new session, check if there is already an active session in the table. You can use a SELECT statement to check if any row has the "active" flag set to true.
SELECT COUNT(*) FROM your_table WHERE active = TRUE;
If the query result is greater than 0, it means there is an active session.
- Based on the result of the previous step, you can either allow or deny the new session request. If the result is 0, then you can proceed with starting the new session. However, if the result is greater than 0, you should reject the new session request.
This approach ensures that only one active session is allowed in the MySQL table by using a flag column to track the active state.