The database is transaction oriented; that is, the database uses transactions to ensure data integrity.A transaction is a series of SQL data manipulation statements that does a logical unit of work.For example, two statements might credit one bank account and debit another.

updating nextval in sequence in oracle-13

CREATE TABLE employees_temp AS SELECT employee_id, first_name, last_name FROM employees; DECLARE emp_id employees_temp.employee_id%TYPE; emp_first_name employees_temp.first_name%TYPE; emp_last_name employees_temp.last_name%TYPE; BEGIN INSERT INTO employees_temp VALUES(299, 'Bob', 'Henry'); UPDATE employees_temp SET first_name = 'Robert' WHERE employee_id = 299; DELETE FROM employees_temp WHERE employee_id = 299 RETURNING first_name, last_name INTO emp_first_name, emp_last_name; COMMIT; DBMS_OUTPUT.

PUT_LINE( emp_first_name || ' ' || emp_last_name); END; / CREATE TABLE employees_temp AS SELECT first_name, last_name FROM employees; DECLARE x VARCHAR2(20) := 'my_first_name'; y VARCHAR2(25) := 'my_last_name'; BEGIN INSERT INTO employees_temp VALUES(x, y); UPDATE employees_temp SET last_name = x WHERE first_name = y; DELETE FROM employees_temp WHERE first_name = x; COMMIT; END; / statement that is explained in Using Native Dynamic SQL.

For information about the use of PL/SQL records with SQL to update and insert data, see Inserting Records Into the Database and Updating the Database with Record Values.

For more information about assigning values to PL/SQL variables, see Assigning SQL Query Results to PL/SQL Variables.

At the end of a transaction that makes database changes, the database makes all the changes permanent or undoes them all.

If your program fails in the middle of a transaction, the database detects the error and rolls back the transaction, restoring the database to its former state. However, there are limitations on the use of pseudocolumns, including the restriction on the use of some pseudocolumns in assignments or conditional tests.For more information, including restrictions, on the use of SQL pseudocolumns, see value of a sequence, the sequence is incremented immediately and permanently, whether you commit or roll back the transaction.After creating a sequence, you can use it to generate unique sequence numbers for transaction processing.Example 6-5 generates a new sequence number and refers to that number in more than one statement. To create a sequence, use the SQL statement CREATE TABLE employees_temp AS SELECT employee_id, first_name, last_name FROM employees; CREATE TABLE employees_temp2 AS SELECT employee_id, first_name, last_name FROM employees; DECLARE seq_value NUMBER; BEGIN -- Generate initial sequence number seq_value := employees_seq.NEXTVAL; -- Print initial sequence number: DBMS_OUTPUT.PUT_LINE ('Initial sequence value: '