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does PHP support foreign key and Rollback?yes or not.if not
then why. how will you done these concept in php?
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Answer Posted / praveen
PHP supports Foreign Keys in InnoDB Storage Engine in
version and above 4.0. It checks the foreign key referential
integrities on Delete and Select statements. If you strictly
needed the foreign keys and speed is not a concern then you
can create table structures using InnoDB Storage Engine.
Where as MyISAM Storage Engines does not allow foreign key
concept. But it will parse the table that contains foreign
keys but wont check the referential integreties. So it is
the job of the designer/programmer to check the desired key
and its dependency in multiple tables.
Let us suppose you have a field F1(primary)in Table1 and
this field is referenced in another tables denoted as (F2,
F3) in tables Table2, Table3......(as a foreign key)
and when you want to perform a DELETE operation/query based
on field F1, then
First you need to write a query to Delete the specified row
in Table1
and you also need to write a query to Delete all
dependent/referenced rows in other tables Table2, Table3...
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