java - Preventing users from deleting records in one table that have related records in another table

Question

I have two tables that relate one-to-many in an Access database. The tables are:

tbluser : UserID [Primary Key]

tblproject : UserID [Foreign Key] , PrjID [Primary Key]

I need to prevent users from deleting any records in tbluser that have related records in the tblproject table.

Answer 1

You need to create a Relationship in the Access database and select the "Enforce Referential Integrity" option:

For detailed instructions on creating Relationships in Access, look here:

Create, edit or delete a relationship

Answer 2

如果您在 tblproject(UserID) 上定义了引用 tbluser(UserID) 的外键约束，则任何用户都无法从 tblproject 中删除该用户，它会抛出一个错误，说明某些内容"Value referencing in tbluser".