Hello, i have this three tables.

Table: Item
Columns: ItemID, Title, Content, NoChange (Date)

Table: Tag
Columns: TagID, Title

Table: ItemTag
Columns: ItemID, TagID

In the Item Table is a Field with NoChange, if this field = true no Tag is allowed to insert a ItemTag value with this ItemID. How can i check this in the insert?

For Updates i have this Statement:

UPDATE ItemTag SET TagID = ? where ItemID = ? 
AND TagID = ? AND exists (
select ItemID from Item where ItemID = ? AND NoChange is null)");

Thank you.