In order to eliminate the possibility of redundancy and the integrity of data, access needs to be designed to split a table into multiple tables, maintaining the relationship between tables and tables through referential integrity.
When designing a table, the field referenced by the table referred to is called the primary key, and the field of the table referencing the primary key is called the foreign key of the table. When you design it, you can enter the relationship button on the Access Software toolbar to design a reference relationship between tables and tables:
Enforce referential integrity: that is, qualifying the foreign key must originate from the reference table's primary key, and access does not allow the foreign key to be empty, which SQL Server 2000 allows
Cascading update Related records: is the reference table's primary key updated, foreign key synchronization automatic Update
Cascade Delete Related records: Is the reference table's primary key deleted, foreign key synchronization Delete
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