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Updating oracle sequence

updating oracle sequence-80

Note: It is not necessary that the key or keys of a table be selected for it to be key preserved.

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This method requires a lock during the transaction and causes multiple users to wait for the next value of the primary key; this waiting is known as .Views can provide a different representation (such as subsets or supersets) of the data that resides within other tables and views.Views are very powerful because they allow you to tailor the presentation of data to different types of users.A table is key-preserved if every key of the table can also be a key of the result of the join.So, a key-preserved table has its keys preserved through a join.When a view is created, Oracle Database expands any wildcard (*) in a top-level view query into a column list.

The resulting query is stored in the data dictionary; any subqueries are left intact.

The column names in an expanded column list are enclosed in quote marks to account for the possibility that the columns of the base object were originally entered with quotes and require them for the query to be syntactically correct.

As an example, assume that the statement, the database can create the view even if the defining query of the view cannot be executed.

EMPNO ENAME DEPTNO DNAME LOC ---------- ---------- ------- -------------- ----------- 7782 CLARK 10 ACCOUNTING NEW YORK 7839 KING 10 ACCOUNTING NEW YORK 7934 MILLER 10 ACCOUNTING NEW YORK 7369 SMITH 20 RESEARCH DALLAS 7876 ADAMS 20 RESEARCH DALLAS 7902 FORD 20 RESEARCH DALLAS 7788 SCOTT 20 RESEARCH DALLAS 7566 JONES 20 RESEARCH DALLAS 8 rows selected.

operation is permitted, because although there are two key-preserved tables, they are the same table. In this case, the delete statement operates on the first table in the EMPNO ENAME DEPTNO DNAME LOC ------- ---------- ------- -------------- ------------- 7369 SMITH 40 OPERATIONS BOSTON 7499 ALLEN 30 SALES CHICAGO 7566 JONES 20 RESEARCH DALLAS 7654 MARTIN 30 SALES CHICAGO 7698 BLAKE 30 SALES CHICAGO 7782 CLARK 10 ACCOUNTING NEW YORK 7788 SCOTT 20 RESEARCH DALLAS 7839 KING 10 ACCOUNTING NEW YORK 7844 TURNER 30 SALES CHICAGO 7876 ADAMS 20 RESEARCH DALLAS 7900 JAMES 30 SALES CHICAGO 7902 FORD 20 RESEARCH DALLAS 7934 MILLER 10 ACCOUNTING NEW YORK 7521 WARD 30 SALES CHICAGO 14 rows selected.

SELECT * FROM Division1_staff; ENAME EMPNO JOB DNAME ------------------------------------------------------ CLARK 7782 MANAGER ACCOUNTING KING 7839 PRESIDENT ACCOUNTING MILLER 7934 CLERK ACCOUNTING ALLEN 7499 SALESMAN SALES WARD 7521 SALESMAN SALES JAMES 7900 CLERK SALES TURNER 7844 SALESMAN SALES MARTIN 7654 SALESMAN SALES BLAKE 7698 MANAGER SALES This error message is returned when a view exists but is unusable due to errors in its query (whether it had errors when originally created or it was created successfully but became unusable later because underlying objects were altered or dropped). Additionally, if a view is a join on other nested views, then the other nested views must be mergeable into the top level view.