Updating a table in pl sql
Oracle Database makes it easy to execute SQL statements (and PL/SQL blocks) dynamically with the EXECUTE IMMEDIATE statement.And querying data is the easiest dynamic SQL operation of all! Here is a generic function that fetches the value of a numeric column in any table, for the specified WHERE clause: CREATE OR REPLACE FUNCTION single_number_value ( table_in IN VARCHAR2, column_in IN VARCHAR2, where_in IN VARCHAR2) RETURN NUMBER IS l_return NUMBER; BEGIN EXECUTE IMMEDIATE 'SELECT ' || column_in || ' FROM ' || table_in || ' WHERE ' || where_in INTO l_return; RETURN l_return; END; As with SELECT-INTO, EXECUTE IMMEDIATE-INTO will raise NO_DATA_FOUND if no rows are found and TOO_MANY_ROWS if more than one row is found.
When that bonus pool is exhausted, it stops fetching and commits all changes.The syntax of this statement is The PL/SQL Challenge question in last issue’s “Wrap Up Your Code in a Neat Package” article focused on how the values assigned to package-level variables persist in your session and asked, “Which of the choices will display ‘3’ after execution?” In the print version of the article, only choice a was correct.Fetch columns from different tables: DECLARE l_last_name employees.last_name%TYPE; l_department_name departments.department_name%TYPE; BEGIN SELECT last_name, department_name INTO l_last_name, l_department_name FROM employees e, departments d WHERE e.department_id=d.department_id AND e.employee_id=138; DBMS_OUTPUT.put_line ( l_last_name || ' in ' || l_department_name); END; the column values in either or both of the tables.So I declare two variables and fetch the two column values into those variables.Dynamic SQL means that at the time you write (and then compile) your code, you do not have all the information you need for parsing a SQL statement.
Instead, you must wait for runtime to complete the SQL statement and then parse and execute it.
Fetch an entire row from the employees table for a specific employee ID: Again, if an employee exists for that ID, the last name will be displayed.
In this case, I declare a record based on the employees table and fetch all columns (with a SELECT *) into that record for the specified row.
If there is no such row, the block will fail with an unhandled NO_DATA_FOUND exception.
Assuming that a unique index is defined on the employee_id column, this block will never raise the TOO_MANY_ROWS exception.
If the statement doesn’t identify any rows to be fetched, Oracle Database will raise the NO_DATA_FOUND exception.