Sql updating tables with foreign keys


18-Dec-2017 19:32

To reflect this in the database, a foreign key column is added to the ORDER table (e.g., CUSTOMERID), which references the primary key of CUSTOMER (e.g. Because the primary key of a table must be unique, and because CUSTOMERID only contains values from that primary key field, we may assume that, when it has a value, CUSTOMERID will identify the particular customer which placed the order.However, this can no longer be assumed if the ORDER table is not kept up to date when rows of the CUSTOMER table are deleted or the ID column altered, and working with these tables may become more difficult.One important part of database design is making sure that relationships between real-world entities are reflected in the database by references, using foreign keys to refer from one table to another.

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A table may have multiple foreign keys, and each foreign key can have a different parent table.You can disable a foreign key constraint during INSERT and UPDATE transactions in SQL Server 2017 by using SQL Server Management Studio or Transact-SQL.