Any of the tables in the MyDNS database may contain a column called active.
If this column exists, it should be an ENUM with two possible values:
First, a value whose meaning is "this row is active". Second, a value whose
meaning is "this row is not active". This could be ENUM('Y','N'),
ENUM('1','0'), ENUM('Active','Inactive'), or whatever you like.
If the active column is present, whenever records are retrieved from
that table, the active column will be honored. If the row is inactive,
it will be as if the row did not exist at all.
The active column must be indexed for good performance.
To create an active column on your soa table, for example, you
might issue SQL statements like this:
mysql> ALTER TABLE mydns.soa ADD COLUMN active ENUM('Y','N') NOT NULL;
Query OK, 66380 rows affected (1.82 sec)
Records: 66380 Duplicates: 0 Warnings: 0
mysql> ALTER TABLE mydns.soa ADD INDEX (active);
Query OK, 66380 rows affected (1.49 sec)
Records: 66380 Duplicates: 0 Warnings: 0