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Synonyms Synonyms are database objects that enable you to cll a table by another name. create an easier reference to a table that is owned by another user.shorten lengthy object nameThis method can be especially useful with lengthy object names, such as views. syntax) CREATE [PUBLIC] SYNONYMS synonym FOR object; PUBLIC : creates a synonyms that is accessible to all users; - The object cannot be ..

Synonyms Synonyms are database objects that enable you to cll a table by another name. create an easier reference to a table that is owned by another user.shorten lengthy object nameThis method can be especially useful with lengthy object names, such as views. syntax) CREATE [PUBLIC] SYNONYMS synonym FOR object; PUBLIC : creates a synonyms that is accessible to all users; - The object cannot be ..

- Create an index on one or more columns: Syntax) CREATE INDEX index ON table (column[,column]...); ex) CREATE INDEX emp_last_name_idx ON employees(last_name);Create an index when: - A column contains a wide range of values - A column contains a large number of null values - One or more columns are frequently used together in a WHERE clause or a join condition - The table is large and most queri..

- Create an index on one or more columns: Syntax) CREATE INDEX index ON table (column[,column]...); ex) CREATE INDEX emp_last_name_idx ON employees(last_name);Create an index when: - A column contains a wide range of values - A column contains a large number of null values - One or more columns are frequently used together in a WHERE clause or a join condition - The table is large and most queri..

An Index:Is a schema objectCan be used by the Oracle server to speed up the retrieval of rows by using a pointer.Can reduce disk I/O by using a rapid path access method to locate data quicklyIs independent of the table that it indexedIs used and maintained automatically by the Oracle server Unique Index : Primary Key or Unique : automatically create an indexNOnunique Index : User created index. ..

An Index:Is a schema objectCan be used by the Oracle server to speed up the retrieval of rows by using a pointer.Can reduce disk I/O by using a rapid path access method to locate data quicklyIs independent of the table that it indexedIs used and maintained automatically by the Oracle server Unique Index : Primary Key or Unique : automatically create an indexNOnunique Index : User created index. ..

Using a Sequence ex) INSERT INTO department (department_id, department_name, location_id) VALUES (dept_deptid_seq.NEXTVAL, 'Support', 2500 ) Tip) View current value SELECT dept_deptid_seq.CURRVAL FROM dual; Caching Sequence Values - Using Cache function : faster access to those values. - Gaps in sequence values can occur when: A rollback occurs The system crashes A sequence is used in another ta..

Using a Sequence ex) INSERT INTO department (department_id, department_name, location_id) VALUES (dept_deptid_seq.NEXTVAL, 'Support', 2500 ) Tip) View current value SELECT dept_deptid_seq.CURRVAL FROM dual; Caching Sequence Values - Using Cache function : faster access to those values. - Gaps in sequence values can occur when: A rollback occurs The system crashes A sequence is used in another ta..

Rules for using NEXTVAL and CURRVAL You can use NEXTVAL and CURRVAL in the following contexts:The SELECT list of a SELECT statement that is not part of a subqueryThe SELECT list of a subquery in an INSERT statementThe VALUES clause of an INSERT statementThe SET clause of an UPDATE statement You cannot use NEXTVAL and CURRVAL in the following context: The SELECT list of a viewA SELECT statement w..

Rules for using NEXTVAL and CURRVAL You can use NEXTVAL and CURRVAL in the following contexts:The SELECT list of a SELECT statement that is not part of a subqueryThe SELECT list of a subquery in an INSERT statementThe VALUES clause of an INSERT statementThe SET clause of an UPDATE statement You cannot use NEXTVAL and CURRVAL in the following context: The SELECT list of a viewA SELECT statement w..