Find the field or areas you want in order to establish as the primary key

To select one to field, click on the row selector for the desired field. To pick multiple industries, hold down the Ctrl trick, and click the brand new line selector for every single industry.

If you would like the transaction of areas within the a multiple-career first the answer to range from the transaction of these fields on the dining table, click Spiders to your toolbar to show the latest Indexes dialog package, right after which reorder industry names with the directory entitled PrimaryKey.

Referential integrity

Referential ethics was a system out-of laws and regulations you to Supply uses in order to guarantee that matchmaking ranging from ideas during the related dining tables are legitimate, and you do not affect remove otherwise alter associated research. You can set referential ethics when all of the pursuing the standards try true:

• This new complimentary industry in the no. 1 dining table is actually a primary trick or possess an alternative list.
• The newest relevant industries have the same investigation method of. There’s two conditions. An AutoNumber profession shall be linked to a number field you to has actually good FieldSize property mode out of Enough time Integer, and an enthusiastic AutoNumber profession who’s got a FieldSize assets setting regarding Duplication ID are going to be linked to a number industry who has a great FieldSize assets setting out of Replication ID.
• Both dining tables get into an equivalent Access databases. In case the tables is connected tables, they must be dining tables inside the Access structure, and also you need discover the databases in which he or she is held setting referential ethics. Referential integrity can not be implemented getting connected tables of database inside other formats.

• You can not go into a value on overseas key field of the new associated dining table that will not can be found however trick of the top table. However, you could get into a good Null value regarding the international key. So it specifies that the information try unrelated. Such as for example, you simply cannot features your order which is assigned to a consumer who would not exists. However, it’s possible to have your order that’s assigned to no body of the typing an excellent Null worth on CustomerID profession.
• You can’t delete a record of an initial desk when the matching suggestions exists inside the a related table. Particularly, you can not delete a member of staff number on the “Employees” dining table if the you will find purchases assigned to the fresh new employee on the “Orders” desk.
• You can’t changes a primary key really worth on priple, you can not alter an enthusiastic employee’s ID from the “Employees” dining table if you’ll find sales allotted to one personnel in the “Orders” table.

Streaming reputation and deletes

To own relationships where referential ethics is implemented, you could potentially establish whether or not you would like Usage of immediately cascade revision or cascade delete relevant details. For individuals who set such solutions, erase boost surgery who would constantly be avoided by referential ethics legislation was permitted. After you erase info or change primary secret philosophy for the an effective first desk, Access helps to make the expected transform to help you relevant dining tables in preserving referential ethics.

For individuals who click to choose the Cascade Change Relevant Industries take a look at package after you define a relationship, when which you replace the first trick from accurate documentation however dining table, Microsoft Access instantly updates the main key to brand new value in most associated information. Eg, for individuals who change datingranking.net/tr/hitwe-inceleme a customer’s ID on “Customers” desk, the brand new CustomerID profession regarding the “Orders” desk is actually automatically up-to-date for every single among you to definitely owner’s commands so that the matchmaking isn’t damaged. Availability cascades status instead demonstrating one content.

In the event the top type in the main dining table was a keen AutoNumber occupation, selecting the Cascade Inform Related Industries evaluate box doesn’t have impression as you don’t change the worth in an AutoNumber career.