foreign key การใช้

• Indeed, a foreign key may itself be a compound key.
• Each foreign key is enforced independently by the database system.
• Therefore, cascading relationships between tables can be established using foreign keys.
• This works because the foreign key holds between attributes with the same name.
• This fact table would be linked to dimensions by means of foreign keys.
• Another recent feature is the configuration of Hierarchic Indexes using foreign key fields.
• A foreign key cannot be mixed like that.
• Reference tables are referenced from Satellites, but never bound with physical foreign keys.
• The foreign key is typically a primary key of an entity it is related to.
• Note that this works because the foreign key holds between attributes with the same name.
• Also, foreign keys are not supported.
• PostgreSQL is triggers, foreign keys; supports functions and stored procedures, and other expandability.
• In Relational database terms, the ReportsTo column is a foreign key referencing the EmpNo column.
• File cross-connects or joins are handled as a synonym definition of the foreign key.
• Each foreign key constraint is dependent upon a unique database index from the parent database table.
• When a PK migrates to another table, it becomes a foreign key in the other table.
• In particular, natural join allows the combination of relations that are associated by a foreign key.
• Database tables in a cache group must each have a defined primary key-foreign key constraints.
• It is also used to decide in which order to load tables with foreign keys in databases.
• For Sqlite2 and MySQL 5.1 . x it provides automatic relation discovery through foreign keys.