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19 mar 2019 · I'm trying to find a query which will return me a list of the foreign keys for a table and the tables and columns they reference. I am half way there with. SELECT a.table_name, a.column_name, a.constraint_name, c.owner FROM ALL_CONS_COLUMNS A, ALL_CONSTRAINTS C where A.CONSTRAINT_NAME = C.CONSTRAINT_NAME and a.table_name=:TableName and C.
A solution to fix this problem is to use the Oracle foreign key constraint to enforce the relationship between rows from the supplier_groups and suppliers tables. First, drop the suppliers table: DROP TABLE suppliers; Code language: SQL (Structured Query Language) (sql) Second, recreate the suppliers table with a foreign key constraint:
See below the updated sql to retrieve the tables that have a foreign key reference to EMPLOYEES. TABLES.foreign_key => EMPLOYEES.primary_key
This Oracle tutorial explains how to use Foreign Keys in Oracle with syntax and examples. A foreign key is a way to enforce referential integrity within your Oracle database. A foreign key means that values in one table must also appear in another table.
Hi Tom, I have two questions about foreign keys. 1). Say table Child references table Parent and the foreign key column P_Id is not null. Then the following two queries should return exactly same results: a: select c.name from child c, parent p where c.p_id = p.p_id; b: select c.name from child c;
The FOREIGN KEY constraint is a key used to link two tables together. A FOREIGN KEY is a field (or collection of fields) in one table that refers to the PRIMARY KEY in another table.
A foreign key constraint requires values in one table to match values in another table. A check constraint requires a value in the database to comply with a specified condition. A REF column by definition references an object in another object type or in a relational table.
