Efficient ways of tracking updates to the database row

Given the following two tables, what are some of the most efficient ways to track updates to a given entit开发者_运维百科y (Entity table) and its data (EntityData).

Entity {

EntityID: Num

EntityData: Blob

}

EntityData {

ID: Num

EntityID: Num

Prop: String

Value: String

Type: Num

}

You can use triggers.

http://dev.mysql.com/doc/refman/5.1/en/create-trigger.html