AWG Blogs

Tuesday, March 16, 2010

MyEDB SQL One Liner

In this case the use case is to reduce the quantity of each product variation ("ron" in myedb speak), i.e. items in a shopping cart, when the total transaction is finalized. The following code can be placed in a transaction inside a MySQL 5.x stored procedure:

update property natural join int_prop natural join entity_property natural join entity
inner join medb_transaction on entity.eid = medb_transaction.eiddst and entity_property.ron = medb_transaction.ron
and property.prop_group_id = medb_transaction.prop_group_id
set int_val = int_val - qty
where medb_transaction.eidsrc = 8 and property.prop_id = 15

The prop_id 15 is the ID of the 'quantity' property. eidsrc is passed as a parameter to the stored procedure and represents the user id (or "eid" for entity id in myedb speak ;) ).

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