REQUEST COMPLIMENTARY SQLS*PLUS LICENCE
Oracle DROP foreign key
After creating a foreign key, you may need to drop the foreign key from the table. You can do this with the ALTER TABLE operator in Oracle/PLSQL.
Syntax to drop a foreign key in Oracle / PLSQL
ALTER TABLE table_name
DROP CONSTRAINT constraint_name;
Example
If you created a foreign key like this:
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)
);
In this example we created the primary key table of the supplier called supplier_pk.
It consists of only one supplier_id field. Then we created a foreign key named fk_supplier in the products table that refers to the supplier table based on the supplier_id field.
If we need to drop the foreign key named fk_supplier, we need to execute the following command:
ALTER TABLE products
DROP CONSTRAINT fk_supplier;
SQL tutorials: SQL Foreign Key Constraint
MORE NEWS
PreambleNoSql is not a replacement for SQL databases but is a valid alternative for many situations where standard SQL is not the best approach for...
PreambleMongoDB Conditional operators specify a condition to which the value of the document field shall correspond.Comparison Query Operators $eq...
5 Database management trends impacting database administrationIn the realm of database management systems, moreover half (52%) of your competitors feel...
The data type is defined as the type of data that any column or variable can store in MS SQL Server. What is the data type? When you create any table or...
PreambleMS SQL Server is a client-server architecture. MS SQL Server process starts with the client application sending a query.SQL Server accepts,...
First the basics: what is the master/slave?One database server (“master”) responds and can do anything. A lot of other database servers store copies of all...
PreambleAtom Hopper (based on Apache Abdera) for those who may not know is an open-source project sponsored by Rackspace. Today we will figure out how to...
PreambleMongoDB recently introduced its new aggregation structure. This structure provides a simpler solution for calculating aggregated values rather...
FlexibilityOne of the most advertised features of MongoDB is its flexibility. Flexibility, however, is a double-edged sword. More flexibility means more...
PreambleSQLShell is a cross-platform command-line tool for SQL, similar to psql for PostgreSQL or MySQL command-line tool for MySQL.Why use it?If you...
PreambleWriting an application on top of the framework on top of the driver on top of the database is a bit like a game on the phone: you say “insert...
PreambleOracle Coherence is a distributed cache that is functionally comparable with Memcached. In addition to the basic function of the API cache, it...
PreambleIBM pureXML, a proprietary XML database built on a relational mechanism (designed for puns) that offers both relational ( SQL / XML ) and...
What is PostgreSQL array? In PostgreSQL we can define a column as an array of valid data types. The data type can be built-in, custom or enumerated....
PreambleIf you are a Linux sysadmin or developer, there comes a time when you need to manage an Oracle database that can work in your environment.In this...
PreambleStarting with Microsoft SQL Server 2008, by default, the group of local administrators is no longer added to SQL Server administrators during the...