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The FOREIGN KEY constraint prevents invalid data from being inserted into the foreign key column, because it has to be one of the values contained in the parent table.FOREIGN KEY on CREATE TABLEThe following SQL creates a FOREIGN KEY on the "PersonID" column when the "Orders" table is ...
SQL FOREIGN KEY ConstraintA FOREIGN KEY in one table points to a PRIMARY KEY in another table.Let's illustrate the foreign key with an example. Look at the following two tables:The "Persons" table:P_IdLastNameFirstNameAddressCity 1 Hansen Ola Timoteivn 10 Sandnes 2 Svendson Tove Borgvn ...
In MySql, you can accomplish that by following Tom Tresansky response, which will give us this syntax: ALTER TABLE `table_name` DROP FOREIGN KEY `key_name`; ALTER TABLE `table_name` ADD CONSTRAINT `constraint_name` FOREIGN KEY (`new_key_name`) REFERENCES `other_table_name` ('other_tabl...
Monday, November 22, 2010 4:05 AM http://www.w3schools.com/sql/sql_foreignkey.asp http://infogoal.com/sql/sql-drop-foreignkey.htm http://stackoverflow.com/questions/482885/how-do-i-drop-a-foreign-key-constraint-if-it-exists-in-sql-server-2005...
How Can I solve this problem ? ASk Doctor DoctorID - primary key UMUser UserID - primary key DoctorID - foreign key relationship to Doctor DoctorID primary key http://www.w3schools.com/sql/sql_foreignkey.asp
SQL FOREIGN KEY on CREATE TABLE The following SQL creates aFOREIGN KEYon the "PersonID" column when the "Orders" table is created: MySQL: CREATETABLEOrders ( OrderID intNOTNULL, OrderNumber intNOTNULL, PersonID int, PRIMARYKEY(OrderID), ...
I'd really like to know how to do the same thing in my code as going into sql server management studio, clicking on the design of a table, and then from the file menu scrolling to the relationships and disabling the foreign key constraint by selecting no to the 'enforce foreign key con...