To pick you to definitely community, click on the line selector with the wanted field. To pick multiple sphere, hold-down brand new Ctrl secret, and click the fresh line selector per industry.
If you prefer your order of the areas into the a simultaneous-career first the answer to range from the order of these sphere from the table, simply click Indexes for the toolbar to demonstrate the new Indexes dialog field, then reorder the field brands into the list called PrimaryKey.
Referential stability was a system from legislation that Availableness uses to help you make certain that dating between facts inside relevant dining tables is legitimate, and you do not affect delete otherwise transform associated study. You might put referential stability when most of the adopting the conditions was true:
- Brand new matching field about no. 1 table is an initial secret or has actually a unique directory.
- The latest associated sphere have a similar research variety of. There have been two exclusions. A keen AutoNumber occupation will likely be connected with a variety community one to have an excellent FieldSize possessions mode uniform dating giriÅŸ of Enough time Integer, and you will an enthusiastic AutoNumber field who has an excellent FieldSize property setting from Replication ID can be connected with a number industry that has a beneficial FieldSize assets form off Duplication ID.
- Each other tables get into an equivalent Availableness database. If your dining tables are linked tables, they have to be dining tables within the Access format, while must open new database where he or she is held setting referential stability. Referential stability can’t be implemented to possess linked dining tables away from databases inside the most other types.
- You can not get into a value from the international trick world of the brand new associated dining table that will not can be found in the main key of the first dining table. But not, you could enter into a good Null value in the international trick. That it specifies your ideas was not related. Such as for example, you cannot enjoys an order that is allotted to a customers who perhaps not are present. Yet not, you’ll have your order which is assigned to no body because of the entering a Null well worth about CustomerID community.
- You simply can’t erase a record out-of a first desk when the coordinating info are present for the a related table. For example, you can not remove a member of staff number from the “Employees” desk when the discover purchases allotted to the fresh new staff member on “Orders” table.
- You simply cannot changes a first key worthy of regarding priple, you can’t changes an employee’s ID regarding “Employees” desk in the event that there are instructions assigned to you to staff member throughout the “Orders” dining table.
Cascading condition and you will deletes
Getting matchmaking where referential stability are implemented, you could indicate if you would like Accessibility instantly cascade change or cascade delete associated suggestions. For individuals who lay these types of selection, erase boost surgery who does constantly be prevented because of the referential integrity rules is actually enabled. When you erase suggestions or changes number 1 trick thinking into the a no. 1 table, Availability helps make the requisite changes so you’re able to associated dining tables to preserve referential ethics.
For folks who mouse click to determine the Cascade Posting Related Fields evaluate box once you establish a relationship, any time that you replace the number 1 secret out-of an archive in the primary desk, Microsoft Availableness immediately condition the primary the answer to the newest well worth throughout relevant facts. Instance, for folks who changes a consumer’s ID on “Customers” dining table, the fresh new CustomerID occupation throughout the “Orders” table is automatically upgraded for every one of you to definitely user’s instructions therefore the relationships is not damaged. Access cascades standing rather than displaying one content.
In case your top type in an important desk is actually an AutoNumber job, selecting the Cascade Change Related Areas glance at package doesn’t have feeling because you usually do not replace the value inside an enthusiastic AutoNumber community.