Lu, Huayi a24ca60074 DWS DEVELOPER 811 version

Reviewed-by: Hasko, Vladimir <vladimir.hasko@t-systems.com>
Co-authored-by: Lu, Huayi <luhuayi@huawei.com>
Co-committed-by: Lu, Huayi <luhuayi@huawei.com>

2023-01-19 13:37:49 +00:00

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CREATE SYNONYM

Function

CREATE SYNONYM is used to create a synonym object. A synonym is an alias of a database object and is used to record the mapping between database object names. You can use synonyms to access associated database objects.

Precautions

The user of a synonym should be its owner.
If the schema name is specified, create a synonym in the specified schema. Otherwise create a synonym in the current schema.
Database objects that can be accessed using synonyms include tables, views, functions, and stored procedures.
To use synonyms, you must have the required permissions on associated objects.
The following DML statements support synonyms: SELECT, INSERT, UPDATE, DELETE, EXPLAIN, and CALL.
The CREATE SYNONYM statement of an associated function or stored procedure cannot be used in a stored procedure. You are advised to use synonyms existing in the pg_synonym system catalog in the stored procedure.

Syntax

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CREATE [ OR REPLACE ] SYNONYM synonym_name 
    FOR object_name;

Parameter Description

synonym
Name of a synonym which is created (optionally with schema names)

Value range: a string. It must comply with the identifier naming rules.
object_name
Name of an object that is associated (optionally with schema names)

Value range: a string. It must comply with the identifier naming rules.

object_name can be the name of an object that does not exist.

Examples

Create schema ot.

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CREATE SCHEMA ot;

Create table ot.t1 and its synonym t1.

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CREATE TABLE ot.t1(id int, name varchar2(10)) DISTRIBUTE BY hash(id);
CREATE OR REPLACE SYNONYM t1 FOR ot.t1;

Use synonym t1.

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SELECT * FROM t1;
INSERT INTO t1 VALUES (1, 'ada'), (2, 'bob');
UPDATE t1 SET t1.name = 'cici' WHERE t1.id = 2;

Create synonym v1 and its associated view ot.v_t1.

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CREATE SYNONYM v1 FOR ot.v_t1;
CREATE VIEW ot.v_t1 AS SELECT * FROM ot.t1;

Use synonym v1.

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SELECT * FROM v1;

Create overloaded function ot.add and its synonym add.

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CREATE OR REPLACE FUNCTION ot.add(a integer, b integer) RETURNS integer AS
$$
SELECT $1 + $2
$$
LANGUAGE sql;

CREATE OR REPLACE FUNCTION ot.add(a decimal(5,2), b decimal(5,2)) RETURNS decimal(5,2) AS
$$
SELECT $1 + $2
$$
LANGUAGE sql;

CREATE OR REPLACE SYNONYM add FOR ot.add;

Use synonym add.

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SELECT add(1,2);
SELECT add(1.2,2.3);

Create stored procedure ot.register and its synonym register.

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CREATE PROCEDURE ot.register(n_id integer, n_name varchar2(10))
SECURITY INVOKER
AS
BEGIN
    INSERT INTO ot.t1 VALUES(n_id, n_name);
END;
/

CREATE OR REPLACE SYNONYM register FOR ot.register;

Use synonym register to invoke the stored procedure.

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CALL register(3,'mia');

Helpful Links

ALTER SYNONYM DROP SYNONYM

Parent topic: DDL Syntax

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