Kingbasees database administrator's Guide -- 15.3 Management synonyms

Catalog

15.3.1.  About synonyms

15.3.2.  Create synonyms

15.3.3.  stay DML Use synonyms in statements

15.3.4.  Delete synonyms

You can create synonyms 、 Tasks such as using synonyms and deleting synonyms .

• About synonyms

It can be a watch 、 View 、 stored procedure , Establish synonyms for database objects such as sequences , You can also create synonyms for synonyms again , You can even create synonyms for a nonexistent object .

• Create synonyms

Use CREATE SYNONYM Statement to create synonyms .

• stay DML Use synonyms in statements

stay DML In the sentence , Synonyms are used in exactly the same way as base objects .

• Delete synonyms

You can DROP SYNONYM Statement to delete a synonym that is no longer needed .

Parent theme ：  Manage views 、 Sequences and synonyms

15.3.1.  About synonyms

It can be a watch 、 View 、 stored procedure , Establish synonyms for database objects such as sequences , You can also create synonyms for synonyms again , You can even create synonyms for a nonexistent object .

The synonym itself does not contain the data or code in the original object , It just acts as a pointer , Is the alias of the database object . Besides , Synonyms are easy to use , And can reduce the database users SQL The complexity of the statement . Synonyms allow underlying objects to be renamed or moved , But synonyms must be redefined , Synonym based applications can continue to work without modification . You can create synonyms for public and private .

The public synonym is named PUBLIC The special user group of has , Generally by DBA establish , Every user in the database can access it . Private synonyms are contained in the schema of a particular user ( Not public Pattern ), Available only for this user and the grantee of the underlying object . Synonyms themselves do not involve safety , When you grant permission to a synonym object , You are essentially granting permissions to the base object of the synonym .

Parent theme ：  Management synonyms

15.3.2.  Create synonyms

Use CREATE SYNONYM Statement to create synonyms .

When creating synonyms , The underlying schema object does not need to exist , You don't need permission to access the object , You can also create synonyms . The following statement is contained in schm In the pattern tab1 Create a table named public_syn_tab1 Public synonym for :

CREATE PUBLIC SYNONYM public_syn_tab1 FOR schm.tab1;

You can also use with OR REPLACE Clause CREATE SYNONYM Replace an existing synonym definition ：

CREATE OR REPLACE PUBLIC SYNONYM public_syn_tab1 FOR schm.tab1;

When creating synonyms, it should be noted that ：

• Synonyms cannot have the same name as other synonyms in the same pattern , But there can be synonyms with the same name in different modes

• Creating a public synonym cannot specify a pattern

• Creating private synonyms cannot specify public Pattern

• To create a private synonym, you must specify a pattern ( In the current mode, the path is public when )

Parent theme ：  Management synonyms

15.3.3.  stay DML Use synonyms in statements

stay DML In the sentence , Synonyms are used in exactly the same way as base objects .

As long as you are given permission to the base object , You can use private synonyms of other users . for example , You only have student Tabular SELECT jurisdiction ,student Table has a synonym stu, At this time , You can only stu Query synonyms , Instead of using it to insert data . Empathy , If you have the insert permission of the base object , You can use its synonyms to insert .

for example , A name is student A synonym for , The following statement is valid ：

INSERT INTO stu VALUES (stu_sequence.CURRVAL, ' Liuens ',18,' Senior high school grade two ',4,'[email protected]',SYSDATE);

Parent theme ：  Management synonyms

15.3.4.  Delete synonyms

You can DROP SYNONYM Statement to delete a synonym that is no longer needed .

If you want to delete public synonyms , You must have DROP PUBLIC SYNONYM System permissions . When deleting private synonyms , Omit PUBLIC keyword ; When deleting public synonyms , Need to include PUBLIC keyword .

for example , The following statement deletes the name syn_test A synonym for ：

DROP SYNONYM syn_test;

The following statement deletes the name public_syn Public synonym for ：

DROP PUBLIC SYNONYM public_syn;

Parent theme ：  Management synonyms