Efficient ways of tracking updates to the database row.

Question

Given the following two tables, what are some of the most efficient ways to track updates to a given entity (Entity table) and its data (EntityData).

Entity {
EntityID: Num
EntityData: Blob
}

EntityData {
ID: Num
EntityID: Num
Prop: String
Value: String
Type: Num
}

Answer 1

You can use triggers.

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