Oracle updating records within same cursor

26-Sep-2015 01:03 by 4 Comments

Oracle updating records within same cursor - private dating websites

You might use sequence numbers to give each row a unique identifier, and refer to those identifiers from other rows to set up parent-child relationships.

Because explicit cursors are so flexible, you can choose from different notations depending on your needs.create table Employee( 2 ID VARCHAR2(4 BYTE) NOT NULL primary key, 3 First_Name VARCHAR2(10 BYTE), 4 Last_Name VARCHAR2(10 BYTE), 5 Start_Date DATE, 6 End_Date DATE, 7 Salary Number(8,2), 8 City VARCHAR2(10 BYTE), 9 Description VARCHAR2(15 BYTE) 10 ) 11 / Table created.SQL select * from Employee 2 / ID FIRST_NAME LAST_NAME START_DAT END_DATE SALARY CITY DESCRIPTION ---- ---------- ---------- --------- --------- ---------- ---------- --------------- 01 Jason Martin 25-JUL-96 25-JUL-06 1234.56 Toronto Programmer 02 Alison Mathews 21-MAR-76 21-FEB-86 6661.78 Vancouver Tester 03 James Smith 12-DEC-78 15-MAR-90 6544.78 Vancouver Tester 04 Celia Rice 24-OCT-82 21-APR-99 2344.78 Vancouver Manager 05 Robert Black 15-JAN-84 08-AUG-98 2334.78 Vancouver Tester 06 Linda Green 30-JUL-87 04-JAN-96 4322.78 New York Tester 07 David Larry 31-DEC-90 12-FEB-98 7897.78 New York Manager 08 James Cat 17-SEP-96 15-APR-02 1232.78 Vancouver Tester 8 rows selected.clause specifying the PL/SQL variable to hold the result: If the query might return more than one row, but you do not care about values after the first, you can restrict any result set to a single row by comparing the value: If the query might return no rows at all, use an exception handler to specify any actions to take when no data is found: If you just want to check whether a condition exists in your data, you might be able to code the query with the record whose field names match the column names from the query, and that exists only during the loop.When you use expressions rather than explicit column names, use column aliases so that you can refer to the corresponding values inside the loop: clauses, depending on the situation.You use the CREATE TABLE employees_temp AS SELECT employee_id, first_name FROM employees; CREATE TABLE employees_temp2 AS SELECT employee_id, first_name FROM employees; DECLARE next_value NUMBER; BEGIN -- The NEXTVAL value is the same no matter what table you select from. NEXTVAL INTO next_value FROM dual; -- You usually use NEXTVAL to create unique numbers when inserting data. NEXTVAL, 'value 1'); -- If you need to store the same value somewhere else, you use CURRVAL. CURRVAL, 'value 1'); -- Because NEXTVAL values might be referenced by different users and -- applications, and some NEXTVAL values might not be stored in the -- database, there might be gaps in the sequence.

END; / DROP TABLE employees_temp; DROP TABLE employees_temp2; statement to organize rows from a database table into a tree structure.

The following sections describe all the query-processing features that explicit cursors provide.

In traditional database programming, you process query results using an internal data structure called a cursor.

In most situations, PL/SQL can manage the cursor for you, so that code to process query results is straightforward and compact.

This section discusses how to process both simple queries where PL/SQL manages everything, and complex queries where you interact with the cursor.

UPDATE emp SET ROW = emp_rec WHERE eno = 100; END; / statements in SQL) and access individual fields or entire rows from the result set.