This document discusses data manipulation in Oracle databases. It describes how to insert, update, and delete rows from tables using DML statements like INSERT, UPDATE, and DELETE. It also covers transaction management using COMMIT, ROLLBACK, and SAVEPOINT statements to control when changes are committed to the database or rolled back. Key aspects covered include inserting new rows, updating and deleting specific rows or all rows, and handling integrity constraints and transactions.

1. Manipulating Data

2. ObjectivesAfter completing this lesson, you should be able to do the following:Describe each DML statementInsert rows into a tableUpdate rows in a tableDelete rows from a tableControl transactions

3. Data Manipulation LanguageA DML statement is executed when you:Add new rows to a tableModify existing rows in a tableRemove existing rows from a tableA transaction consists of a collection of DML statements that form a logical unit of work.

4. Adding a New Row to a Table50DEVELOPMENTDETROITNew row“…insert a new row into DEPT table…”50DEVELOPMENTDETROITDEPT DEPTNO DNAME LOC ------ ---------- --------10ACCOUNTINGNEW YORK20RESEARCHDALLAS30SALESCHICAGO40OPERATIONSBOSTONDEPT DEPTNO DNAME LOC ------ ---------- --------10ACCOUNTINGNEW YORK20RESEARCHDALLAS30SALESCHICAGO40OPERATIONSBOSTON

5. The INSERT StatementAdd new rows to a table by using the INSERT statement.Only one row is inserted at a time with this syntax.INSERT INTOtable [(column [, column...])]VALUES(value [, value...]);

6. Inserting New RowsInsert a new row containing values for each column.List values in the default order of the columns in the table. Optionally list the columns in the INSERT clause.Enclose character and date values within single quotation marks.SQL> INSERT INTOdept (deptno, dname, loc)2 VALUES (50, 'DEVELOPMENT', 'DETROIT');1 row created.

7. Inserting Rows with Null ValuesImplicit method: Omit the column from the column list.SQL> INSERT INTOdept (deptno, dname )2 VALUES (60, 'MIS');1 row created.Explicit method: Specify the NULL keyword.SQL> INSERT INTOdept2 VALUES (70, 'FINANCE', NULL);1 row created.

8. Inserting Special ValuesThe SYSDATE function records the current date and time.SQL> INSERT INTOemp (empno, ename, job,2mgr, hiredate, sal, comm,3deptno)4 VALUES (7196, 'GREEN', 'SALESMAN',57782, SYSDATE, 2000, NULL,610);1 row created.

9. Inserting Specific Date ValuesAdd a new employee.SQL> INSERT INTO emp2 VALUES (2296,'AROMANO','SALESMAN',7782,3 TO_DATE('FEB 3, 97', 'MON DD, YY'),41300, NULL, 10);1 row created.Verify your addition.EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO----- ------- -------- ---- --------- ---- ---- ------2296 AROMANO SALESMAN 778203-FEB-97130010

10. Inserting Values by Using Substitution VariablesCreate an interactive script by using SQL*Plus substitution parameters.SQL> INSERT INTOdept (deptno, dname, loc)2 VALUES (&department_id,3 '&department_name', '&location');Enter value for department_id: 80Enter value for department_name: EDUCATIONEnter value for location: ATLANTA1 row created.

11. Creating a Script with Customized PromptsACCEPT stores the value in a variable.PROMPT displays your customized text.ACCEPTdepartment_id PROMPT 'Please enter the -department number:'ACCEPT department_name PROMPT 'Please enter -the department name:'ACCEPTlocation PROMPT 'Please enter the -location:'INSERT INTO dept (deptno, dname, loc)VALUES (&department_id, '&department_name','&location');

12. Copying Rows from Another TableWrite your INSERT statement with a subquery.Do not use the VALUES clause.Match the number of columns in the INSERT clause to those in the subquery.SQL> INSERT INTO managers(id, name, salary, hiredate)2SELECTempno, ename, sal, hiredate3FROM emp4WHEREjob = 'MANAGER';3 rows created.

13. Changing Data in a Table“…update a row in EMP table…”20EMP EMPNO ENAME JOB ... DEPTNO 7839KINGPRESIDENT107698BLAKEMANAGER307782CLARKMANAGER107566JONESMANAGER20 ...EMP EMPNO ENAME JOB ... DEPTNO 7839KINGPRESIDENT107698BLAKEMANAGER307782CLARKMANAGER107566JONESMANAGER20 ...

14. The UPDATE StatementModify existing rows with the UPDATE statement.Update more than one row at a time, if required.UPDATEtableSETcolumn = value [, column = value, ...][WHERE condition];

15. Updating Rows in a TableSpecific row or rows are modified when you specify the WHERE clause.All rows in the table are modified if you omit the WHERE clause.SQL> UPDATE emp2 SET deptno = 203 WHERE empno = 7782;1 row updated.SQL> UPDATE employee2 SET deptno = 20;14 rows updated.

16. Updating with Multiple-Column SubqueryUpdate employee 7698’s job and department to match that of employee 7499.SQL> UPDATE emp2 SET (job, deptno) = 3 (SELECT job, deptno4 FROM emp5 WHERE empno = 7499)6 WHERE empno = 7698;1 row updated.

17. Updating Rows Based on Another TableUse subqueries in UPDATE statements to update rows in a table based on values from another table.SQL>UPDATEemployee2SETdeptno = (SELECTdeptno3FROMemp 4WHEREempno = 7788)5WHEREjob = (SELECTjob6FROMemp7WHEREempno = 7788);2 rows updated.

18. SQL> UPDATEemp2 SETdeptno = 553 WHEREdeptno = 10;UPDATE emp *ERROR at line 1:ORA-02291: integrity constraint (USR.EMP_DEPTNO_FK) violated - parent key not foundUpdating Rows: Integrity Constraint ErrorDepartment number 55 does not exist

19. “…delete a row from DEPT table…”Removing a Row from a Table DEPT DEPTNO DNAME LOC ------ ---------- --------10ACCOUNTINGNEW YORK20RESEARCHDALLAS30SALESCHICAGO40OPERATIONSBOSTON60MIS ...DEPT DEPTNO DNAME LOC ------ ---------- --------10ACCOUNTINGNEW YORK20RESEARCHDALLAS30SALESCHICAGO40OPERATIONSBOSTON50DEVELOPMENTDETROIT60MIS ...

20. The DELETE StatementYou can remove existing rows from a table by using the DELETE statement.DELETE [FROM] table[WHEREcondition];

21. Specific rows are deleted when you specify the WHERE clause.All rows in the table are deleted if you omit the WHERE clause.Deleting Rows from a TableSQL> DELETE FROMdepartment2 WHERE dname = 'DEVELOPMENT'; 1 row deleted.SQL> DELETE FROMdepartment;4 rows deleted.

22. Deleting Rows Based on Another TableUse subqueries in DELETE statements to remove rows from a table based on values from another table.SQL> DELETE FROMemployee2 WHEREdeptno = 3 (SELECT deptno4 FROM dept5 WHERE dname ='SALES');6 rows deleted.

23. Deleting Rows: Integrity Constraint ErrorSQL> DELETE FROMdept2 WHEREdeptno = 10;You cannot delete a row that contains a primary key that is used as a foreign key in another table.DELETE FROM dept *ERROR at line 1:ORA-02292: integrity constraint (USR.EMP_DEPTNO_FK) violated - child record found

24. Database TransactionsConsist of one of the following statements:DML statements that make up one consistent change to the dataOne DDL statementOne DCL statement

25. Database TransactionsBegin when the first executable SQL statement is executedEnd with one of the following events:COMMIT or ROLLBACK is issuedDDL or DCL statement executes (automatic commit)User exitsSystem crashes

26. Advantages of COMMIT and ROLLBACK StatementsEnsure data consistencyPreview data changes before making changes permanentGroup logically related operations

27. Controlling TransactionsINSERTDELETEINSERTINSERTUPDATEDELETEROLLBACK to Savepoint BROLLBACK to Savepoint AROLLBACKTransactionUPDATEINSERTSavepoint ASavepoint BCOMMIT

28. An automatic commit occurs under the following circumstances:DDL statement is issuedDCL statement is issuedNormal exit from SQL*Plus, without explicitly issuing COMMIT or ROLLBACKAn automatic rollback occurs under an abnormal termination of SQL*Plus or a system failure.Implicit Transaction Processing

29. State of the Data Before COMMIT or ROLLBACKThe previous state of the data can be recovered.The current user can review the results of the DML operations by using the SELECT statement.Other users cannot view the results of the DML statements by the current user.The affected rows are locked; other users cannot change the data within the affected rows.

30. State of the Data After COMMITData changes are made permanent in the database.The previous state of the data is permanently lost.All users can view the results.Locks on the affected rows are released; those rows are available for other users to manipulate.All savepoints are erased.

31. Committing DataMake the changes.SQL> UPDATEemp2 SET deptno = 103 WHEREempno = 7782;1 row updated.Commit the changes.SQL> COMMIT;Commit complete.

32. State of the Data After ROLLBACKDiscard all pending changes by using the ROLLBACK statement.Data changes are undone.Previous state of the data is restored.Locks on the affected rows are released.SQL> DELETE FROMemployee;14 rows deleted.SQL> ROLLBACK;Rollback complete.

33. Rolling Back Changes to a MarkerCreate a marker in a current transaction by using the SAVEPOINT statement.Roll back to that marker by using the ROLLBACK TO SAVEPOINT statement.SQL> UPDATE...SQL> SAVEPOINT update_done;Savepoint created.SQL> INSERT...SQL> ROLLBACK TO update_done;Rollback complete.

34. Statement-Level RollbackIf a single DML statement fails during execution, only that statement is rolled back.The Oracle Server implements an implicit savepoint.All other changes are retained.The user should terminate transactions explicitly by executing a COMMIT or ROLLBACK statement.

35. Read ConsistencyRead consistency guarantees a consistent view of the data at all times.Changes made by one user do not conflict with changes made by another user. Read consistency ensures that on the same data:Readers do not wait for writersWriters do not wait for readers

36. Implementation of Read ConsistencyDatablocksUPDATE empSET sal = 2000WHERE ename = 'SCOTT';RollbacksegmentsUser Achangedand unchanged dataSELECT *FROMemp;Readconsistentimagebefore change“old” dataUser B

37. LockingOracle locks:Prevent destructive interaction between concurrent transactionsRequire no user actionAutomatically use the lowest level of restrictivenessAre held for the duration of the transactionHave two basic modes: ExclusiveShare

38. SummaryDescriptionAdds a new row to the tableModifies existing rows in the tableRemoves existing rows from the tableMakes all pending changes permanentAllows a rollback to the savepoint markerDiscards all pending data changesStatementINSERTUPDATEDELETECOMMITSAVEPOINTROLLBACK

39. Practice OverviewInserting rows into the tablesUpdating and deleting rows in the tableControlling transactions