add constraint fk
ALTER TABLE Orders
ADD CONSTRAINT FK_PersonOrder
FOREIGN KEY (PersonID) REFERENCES Persons(PersonID);add constraint fk
ALTER TABLE Orders
ADD CONSTRAINT FK_PersonOrder
FOREIGN KEY (PersonID) REFERENCES Persons(PersonID);foreign key plsql
CREATE TABLE supplier
( supplier_id numeric(10) not null,
supplier_name varchar2(50) not null,
contact_name varchar2(50),
CONSTRAINT supplier_pk PRIMARY KEY (supplier_id)
);
CREATE TABLE products
( product_id numeric(10) not null,
supplier_id numeric(10) not null,
CONSTRAINT fk_supplier
FOREIGN KEY (supplier_id)
REFERENCES supplier(supplier_id)
);foreign key oracle
ALTER TABLE table_name
ADD CONSTRAINT constraint_name
FOREIGN KEY (column1, column2, ... column_n)
REFERENCES parent_table (column1, column2, ... column_n);
Example
ALTER TABLE products
ADD CONSTRAINT fk_supplier
FOREIGN KEY (supplier_id)
REFERENCES supplier(supplier_id);foreign key on table oracle
SELECT c.OWNER, a.TABLE_NAME, a.COLUMN_NAME, a.CONSTRAINT_NAME,
c.R_OWNER AS REF_OWNER, cpk.TABLE_NAME AS REF_TABLE,
cpk.CONSTRAINT_NAME AS REF_PK
FROM ALL_CONS_COLUMNS a
JOIN ALL_CONSTRAINTS c ON a.OWNER = c.OWNER
AND a.CONSTRAINT_NAME = c.CONSTRAINT_NAME
JOIN ALL_CONSTRAINTS cpk ON c.R_OWNER = cpk.OWNER
AND c.R_CONSTRAINT_NAME = cpk.CONSTRAINT_NAME
WHERE c.CONSTRAINT_TYPE = 'R' AND c.TABLE_NAME= 'table_name';Copyright © 2021 Codeinu
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