MyRO implements a per-record database tables privilege system in MySQL. All database servers implement a privilege system based on tables or columns, that is if a user has grants to access a certain table (or a table's column) he can access all records of that table (or that table's column). MyRO lets you specify grants on a record level so a user can access only those records it is allowed to. A consequence of this is that different users reading the same table will see different records. The grant mechanism provided by MyRO is similar to that of a Unix file system, that is each record belongs to an owner and a group and has three sets of permissions associated (for the owner, the users belonging to the group and all other users) that specify whether that record can be read and/or written.

Please see the documentation.