This example illustrates foreign key definition using the SQL Distributed Management Objects (SQL-DMO) Key object. In the example, adding the Key object to the Keys collection creates a FOREIGN KEY constraint on the referenced table. 复制 ' Create a FOREIGN KEY constraint on the ' Northwind.....
CREATE TABLE first ( a INTEGER, PRIMARY KEY (a) ) ; and CREATE TABLE second ( b INTEGER, aref INTEGER, PRIMARY KEY (b), KEY (aref) ); ALTER TABLE second ADD CONSTRAINT myforeignkey FOREIGN KEY (aref) REFERENCES first(a); Is there any restriction derived from the ...
# ALTER TABLE `db2`.`document` DROP FOREIGN KEY document_ibfk_1, ADD CONSTRAINT document_ibfk_1 FOREIGN KEY(userId) REFERENCES `db1`.`user`(id); # # Transformation for reverse changes (--changes-for=server2): # # ALTER TABLE `db1`.`document` # DROP FOREIGN KEY document_ibfk_1, ...
Knowledge Base » Training & Tutorials » Advanced MariaDB Articles » Development Articles » MariaDB Internals Documentation » Using MariaDB with Your Programs (API) » Error Codes » MariaDB Error Codes 1800 to 1899 » Error 1851: Adding foreign keys needs foreign_key_checks=OFF...
create_table :authors_books, id: false do |t| t.references :author, foreign_key: true, null: false t.references :book, foreign_key: true, null: false end After adding data for a short while, we realized that using has_many :through would not work without a primary key on the author...
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mysql> mysql> ALTER TABLE remote_archives DROP insert_worker, ALGORITHM=INPLACE, LOCK=NONE; ERROR 1062 (23000): Duplicate entry '1379' for key 'PRIMARY' mysql> mysql> ALTER TABLE remote_archives ADD insert_worker integer, ALGORITHM=INPLACE, LOCK=NONE; ERROR 1060 (42S21): Duplicate column ...
3550 Peter Steiner December 03, 2010 03:07AM Re: Which restriction has adding a foreign key constraint in ALTER TABLE command? 1445 Boris Masnec December 08, 2010 01:15PM Sorry, you can't reply to this topic. It has been closed.