1. kaiumkuakata@gmail.com : Ab kaium : Ab kaium
  2. akaskuakata@gmail.com : akas :
  3. mithukuakata@gmail.com : mithu :
  4. mizankuakata@gmail.com : mizan :
  5. habibullahkhanrabbi@gmail.com : rabbi :
  6. amaderkuakata.r@gmail.com : rumi sorif : rumi sorif
রবিবার, ২৫ সেপ্টেম্বর ২০২২, ০৭:২৭ পূর্বাহ্ন
প্রতিটি জেলা উপজেলায় প্রতিনিধি নিয়োগ দেওয়া হবে। যোগাযোগঃ-০১৯১১১৪৫০৯১, ০১৭১২৭৪৫৬৭৪

Discover profession otherwise areas you want to help you define as the the main secret

  • আপডেট সময় বুধবার, ১৩ জুলাই, ২০২২
  • ১১ বার

Discover profession otherwise areas you want to help you define as the the main secret

To choose you to definitely career, click the row selector into the wanted field. To select several areas, hold-down new Ctrl trick, and click the new row selector each industry.

If you want your order of your industries within the a parallel-occupation number one key to differ from the order of these industries throughout the desk, click Spiders to the toolbar to exhibit the new Spiders dialog container, then reorder industry names to the list titled PrimaryKey.

Referential stability

Referential ethics is actually a network away from laws you to Access spends to make sure that dating anywhere between suggestions in the relevant tables was good, and that you do not accidentally remove otherwise changes relevant studies. You could set referential integrity whenever all adopting the criteria are true:

  • The brand new complimentary community regarding the top desk was a first trick otherwise has a different sort of list.
  • The fresh associated areas have the same investigation type of. There are 2 conditions. An AutoNumber occupation is going to be connected with several job you to definitely provides a FieldSize possessions mode from Enough time Integer, and an AutoNumber job who’s a great FieldSize possessions form off Duplication ID would be pertaining to several occupation who has got a FieldSize property setting away from Replication ID.
  • Both tables fall under the same Supply databases. Should your tables are connected tables, they have to be dining tables inside Availability structure, and you also need discover the new database in which they are stored to create referential stability. Referential integrity cannot be enforced having connected dining tables off database during the most other types.
  • You can not go into a value throughout the international key arena of the relevant dining table that will not can be found in the primary key of primary table. Yet not, you could get into an effective Null worth regarding international secret. It determine the details try not related. Such as for example, you simply cannot has actually your order which is assigned to a customer who perhaps not can be found. However, you will get your order that is allotted to not one person by entering an excellent Null value on CustomerID occupation.
  • You simply cannot remove an archive away from a first desk in the event the matching details are present inside an associated table. Including, you can not delete an employee listing about “Employees” dining table when the discover orders assigned to brand new employee on “Orders” desk.
  • You cannot alter a first key worthy of regarding the priple, you cannot change an enthusiastic employee’s ID regarding the “Employees” table in the event that you can find sales allotted to you to definitely worker regarding “Orders” desk.

Streaming position and you may deletes

Having matchmaking where referential ethics was implemented, you could potentially establish whether you want The means to access immediately cascade modify otherwise cascade erase related information. For many who lay these alternatives, erase and update operations who does always be avoided by referential integrity legislation are permitted. After you erase ideas or transform number one secret values for the an effective no. 1 table, Availability helps make https://datingranking.net/tr/interracial-dating-central-inceleme/ the required changes so you’re able to related tables in preserving referential integrity.

For folks who click to choose the Cascade Enhance Related Sphere see field once you explain a romance, at any time you alter the primary key out of an archive in the main dining table, Microsoft Supply immediately reputation the key key to the new worthy of in all related suggestions. Such, for folks who changes a consumer’s ID regarding the “Customers” desk, the fresh new CustomerID industry from the “Orders” dining table is instantly current for each certainly one owner’s sales therefore the relationships is not busted. Access cascades status instead of displaying any message.

In case your first type in the primary desk is an enthusiastic AutoNumber profession, choosing the Cascade Upgrade Related Fields evaluate container has no feeling since you dont change the really worth from inside the an AutoNumber career.

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