ObjectivesObjectives
After completing this lesson, you should be able to do the following:Describe each DML statement Insert rows into a tableUpdate rows in a tableDelete rows from a tableControl transactions
After completing this lesson, you should be able to do the following:Describe each DML statement Insert rows into a tableUpdate rows in a tableDelete rows from a tableControl transactions
Data Manipulation LanguageData Manipulation Language
A DML statement is executed when you:Add new rows to a tableModify existing rows in a tableRemove existing rows from a table
A transaction consists of a collection of DML statements that form a logical unit of work.
A DML statement is executed when you:Add new rows to a tableModify existing rows in a tableRemove existing rows from a table
A transaction consists of a collection of DML statements that form a logical unit of work.
Adding a New Row to a TableAdding a New Row to a Table
DEPT DEPT DEPTNO DNAME LOC ------ ---------- -------- 10 ACCOUNTING NEW YORK 20 RESEARCH DALLAS 30 SALES CHICAGO 40 OPERATIONS BOSTON
New rowNew row
50 DEVELOPMENT DETROIT
DEPT DEPT DEPTNO DNAME LOC ------ ---------- -------- 10 ACCOUNTING NEW YORK 20 RESEARCH DALLAS 30 SALES CHICAGO 40 OPERATIONS BOSTON
“…“…insert a new row insert a new row into DEPT table…”into DEPT table…”
50 DEVELOPMENT DETROIT
The INSERT StatementThe INSERT Statement
Add new rows to a table by using the INSERT statement.
Only one row is inserted at a time with this syntax.
Add new rows to a table by using the INSERT statement.
Only one row is inserted at a time with this syntax.
INSERT INTO table [(column [, column...])]VALUES (value [, value...]);
INSERT INTO table [(column [, column...])]VALUES (value [, value...]);
Inserting New RowsInserting New Rows
Insert 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.
Insert 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 INTO dept (deptno, dname, loc) 2 VALUES (50, 'DEVELOPMENT', 'DETROIT');1 row created.1 row created.
Inserting Rows with Null ValuesInserting Rows with Null Values
Implicit method: Omit the column from the column list.
Implicit method: Omit the column from the column list.
SQL> INSERT INTO dept (deptno, dname ) 2 VALUES (60, 'MIS');1 row created.1 row created.
• Explicit method: Specify the NULL keyword.
• Explicit method: Specify the NULL keyword.
SQL> INSERT INTO dept 2 VALUES (70, 'FINANCE', NULL);1 row created.1 row created.
Inserting Special ValuesInserting Special Values
The SYSDATE function records the current date and time.The SYSDATE function records the current date and time.
SQL> INSERT INTO emp (empno, ename, job, 2 mgr, hiredate, sal, comm, 3 deptno) 4 VALUES (7196, 'GREEN', 'SALESMAN', 5 7782, SYSDATE, 2000, NULL, 6 10);1 row created.1 row created.
The slide example records information for employee Green in the EMP table. It supplies the current date and time in the HIREDATE column. It uses the SYSDATE function for current date and time.
Inserting Specific Date ValuesInserting Specific Date ValuesAdd a new employee.Add a new employee.
SQL> INSERT INTO emp 2 VALUES (2296,'AROMANO','SALESMAN',7782, 3 TO_DATE('FEB 3, 97', 'MON DD, YY'), 4 1300, NULL, 10);1 row created.1 row created.
• Verify your addition.• Verify your addition.EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO----- ------- -------- ---- --------- ---- ---- ------ 2296 AROMANO SALESMAN 7782 03-FEB-97 1300 10
If a date is required to be entered in a format other than the default (for example, another century) and/or a specific time is required, use the TO_DATE function.
The example on the slide records information for employee Aromano in the EMP table. It sets the HIREDATE column to be February 3, 1997.
Inserting Values by Using Substitution Variables
Inserting Values by Using Substitution Variables
Create an interactive script by using SQL*Plus substitution parameters.Create an interactive script by using SQL*Plus substitution parameters.
SQL> INSERT INTO dept (deptno, dname, loc) 2 VALUES (&department_id, 3 '&department_name', '&location');
Enter value for department_id: 8080Enter value for department_name: EDUCATIONEDUCATIONEnter value for location: ATLANTAATLANTA
1 row created.
If you want to insert another rows, type run after the SQL prompt
Creating a Script with Customized Prompts
Creating a Script with Customized Prompts
ACCEPT stores the value in a variable.PROMPT displays your customized text.
ACCEPT stores the value in a variable.PROMPT displays your customized text.
ACCEPT department_id PROMPT 'Please enter the -
department number:'
ACCEPT department_name PROMPT 'Please enter -
the department name:'
ACCEPT location PROMPT 'Please enter the -
location:'
INSERT INTO dept (deptno, dname, loc)
VALUES (&department_id, '&department_name',
'&location');
Creating a Script to Manipulate Data
You can save your command with substitution variables to a file and execute the file. Each time you execute the command, it will prompt you for new values. Customize the prompts by using the SQL*Plus ACCEPT command.
The example on the slide records information for a department in the DEPT table. It prompts the user for the department number, department name, and location by using customized prompt messages.
Please enter the department number: 90
Please enter the department name: PAYROLL
Please enter the location: HOUSTON
1 row created.
Do not prefix the SQL*Plus substitution parameter with the ampersand (&) when referencing it in the ACCEPT command. Use a dash (-) to continue a SQL*Plus command on the next line.
.
SQL> CREATE TABLE MANAGERs (ID NUMBER(4),
2 NAME VARCHAR2(10), SALARY NUMBER(7,2), 3 HIREDATE DATE);
جدول تكوين تم
Copying Rows from Another Table
Copying Rows from Another Table
Write 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.
Write 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) 2 SELECT empno, ename, sal, hiredate 3 FROM emp 4 WHERE job = 'MANAGER';3 rows created.3 rows created.
Changing Data in a TableChanging Data in a TableEMPEMP
“…“…update a row update a row in EMP table…”in EMP table…”
EMPEMP
EMPNO ENAME JOB ... DEPTNO
7839 KING PRESIDENT 10 7698 BLAKE MANAGER 30 7782 CLARK MANAGER 10 7566 JONES MANAGER 20 ...
20
EMPNO ENAME JOB ... DEPTNO
7839 KING PRESIDENT 10 7698 BLAKE MANAGER 30 7782 CLARK MANAGER 10 7566 JONES MANAGER 20 ...
The UPDATE StatementThe UPDATE Statement
Modify existing rows with the UPDATE statement.
Update more than one row at a time, if required.
Modify existing rows with the UPDATE statement.
Update more than one row at a time, if required.
UPDATE tableSET column = value [, column = value, ...][WHERE condition];
UPDATE tableSET column = value [, column = value, ...][WHERE condition];
Updating Rows in a TableUpdating 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.
Specific 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 emp 2 SET deptno = 20 3 WHERE empno = 7782;1 row updated.1 row updated.
SQL> UPDATE employee 2 SET deptno = 20;14 rows updated.14 rows updated.
SQL> UPDATE employee 2 SET deptno = 20;14 rows updated.14 rows updated.
Updating with Multiple-Column Subquery
Updating with Multiple-Column Subquery
SQL> UPDATE emp 2 SET (job, deptno) = 3 (SELECT job, deptno 4 FROM emp 5 WHERE empno = 7499) 6 WHERE empno = 7698;1 row updated.1 row updated.
Update employee 7698’s job and department to match that of employee 7499.Update employee 7698’s job and department to match that of employee 7499.
Updating Rows Based on Another Table
Updating Rows Based on Another Table
Use subqueries in UPDATE statements to update rows in a table based on values from another table.Use subqueries in UPDATE statements to update rows in a table based on values from another table.
SQL> UPDATE emp 2 SET deptno = (SELECT deptno 3 FROM emp 4 WHERE empno = 7499) 5 WHERE job = (SELECT job 6 FROM emp 7 WHERE empno = 7788);2 rows updated.2 rows updated.
SQL> UPDATE emp 2 SET deptno = (SELECT deptno 3 FROM emp 4 WHERE empno = 7499) 5 WHERE job = (SELECT job 6 FROM emp 7 WHERE empno = 7788);2 rows updated.2 rows updated.
UPDATE emp *ERROR at line 1:ORA-02291: integrity constraint (USR.EMP_DEPTNO_FK) violated - parent key not found
UPDATE emp *ERROR at line 1:ORA-02291: integrity constraint (USR.EMP_DEPTNO_FK) violated - parent key not found
SQL> UPDATE emp 2 SET deptno = 55 3 WHERE deptno = 10;
SQL> UPDATE emp 2 SET deptno = 55 3 WHERE deptno = 10;
Updating Rows: Integrity Constraint Error
Updating Rows: Integrity Constraint Error
Department n
umber 55 does n
ot
existDepartm
ent number 5
5 does not
exist
“…“…delete a row delete a row from DEPT table…”from DEPT table…”
Removing a Row from a Table Removing a Row from a Table DEPT DEPT DEPTNO DNAME LOC ------ ---------- -------- 10 ACCOUNTING NEW YORK 20 RESEARCH DALLAS 30 SALES CHICAGO 40 OPERATIONS BOSTON 50 DEVELOPMENT DETROIT 60 MIS ...
DEPT DEPT DEPTNO DNAME LOC ------ ---------- -------- 10 ACCOUNTING NEW YORK 20 RESEARCH DALLAS 30 SALES CHICAGO 40 OPERATIONS BOSTON 60 MIS ...
The DELETE StatementThe DELETE Statement
You can remove existing rows from a table by using the DELETE statement.You can remove existing rows from a table by using the DELETE statement.
DELETE [FROM] table[WHERE condition];
DELETE [FROM] table[WHERE condition];
Deleting Rows
You can remove existing rows by using the DELETE statement.
In the syntax:
table is the table namecondition identifies the rows to be deleted and is composed of column
names, expressions, constants, subqueries, and comparison operators
Specific rows are deleted when you specify the WHERE clause.
All rows in the table are deleted if you omit the WHERE clause.
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 TableDeleting Rows from a Table
SQL> DELETE FROM dept 2 WHERE dname = 'DEVELOPMENT'; 1 row deleted.1 row deleted.
SQL> DELETE FROM dept 2 WHERE dname = 'DEVELOPMENT'; 1 row deleted.1 row deleted.
SQL> DELETE FROM department;4 rows deleted.4 rows deleted.
SQL> DELETE FROM department;4 rows deleted.4 rows deleted.
The slide example deletes the DEVELOPMENT department from the DEPARTMENT table
The second example on the slide deletes all the rows from the DEPARTMENT table because no WHERE clause has been specified.
Deleting Rows Based on Another Table
Deleting Rows Based on Another Table
Use subqueries in DELETE statements to remove rows from a table based on values from another table.
Use subqueries in DELETE statements to remove rows from a table based on values from another table.
SQL> DELETE FROM emp 2 WHERE deptno = 3 (SELECT deptno 4 FROM dept 5 WHERE dname ='SALES');6 rows deleted.6 rows deleted.
The example on the slide deletes all the employees who are in department 30. The subquery searches the DEPT table to find the department number for the SALES department.
Deleting Rows: Integrity Constraint Error
Deleting Rows: Integrity Constraint Error
SQL> DELETE FROM dept 2 WHERE deptno = 10;
SQL> DELETE FROM dept 2 WHERE deptno = 10;
DELETE FROM dept *ERROR at line 1:ORA-02292: integrity constraint (USR.EMP_DEPTNO_FK) violated - child record found
DELETE FROM dept *ERROR at line 1:ORA-02292: integrity constraint (USR.EMP_DEPTNO_FK) violated - child record found
You cannot delete a row
that contains a primary key
that is used as a foreign
key
in another table.
You cannot delete a row
that contains a primary key
that is used as a foreign
key
in another table.
Database TransactionsDatabase Transactions
Consist of one of the following statements:DML statements that make up one
consistent change to the dataOne DDL statementOne DCL statement
Consist of one of the following statements:DML statements that make up one
consistent change to the dataOne DDL statementOne DCL statement
Database TransactionsDatabase Transactions
Begin when the first executable SQL statement is executed
End with one of the following events:COMMIT or ROLLBACK is issuedDDL or DCL statement executes (automatic
commit)User exitsSystem crashes
Begin when the first executable SQL statement is executed
End with one of the following events:COMMIT or ROLLBACK is issuedDDL or DCL statement executes (automatic
commit)User exitsSystem crashes
Advantages of COMMIT and ROLLBACK Statements
Advantages of COMMIT and ROLLBACK Statements
Ensure data consistencyPreview data changes before making
changes permanentGroup logically related operations
Ensure data consistencyPreview data changes before making
changes permanentGroup logically related operations
DELETEDELETE
Controlling TransactionsControlling TransactionsTransactionTransaction
Savepoint ASavepoint A
ROLLBACK to Savepoint BROLLBACK to Savepoint B
DELETEDELETE
Savepoint BSavepoint BCOMMITCOMMIT
INSERTINSERTUPDATEUPDATE
ROLLBACK to Savepoint AROLLBACK to Savepoint A
INSERTINSERTUPDATEUPDATEINSERTINSERT
ROLLBACKROLLBACK
INSERTINSERT
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.
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
Implicit Transaction Processing
State of the Data Before COMMIT or ROLLBACK
State of the Data Before COMMIT or ROLLBACK
The 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.
The 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.
State of the Data After COMMIT
State of the Data After COMMIT
Data 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.
Data 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.
Committing DataCommitting Data
SQL> UPDATE emp 2 SET deptno = 10 3 WHERE empno = 7782;1 row updated.1 row updated.
SQL> UPDATE emp 2 SET deptno = 10 3 WHERE empno = 7782;1 row updated.1 row updated.
Make the changes.Make the changes.
• Commit the changes.• Commit the changes.SQL> COMMIT;Commit complete.Commit complete.
The slide example updates the EMP table and sets the department number for employee 7782 (Clark) to 10. It then makes the change permanent by issuing the COMMIT statement.
State of the Data After ROLLBACK
State of the Data After ROLLBACK
Discard 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.
Discard 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 FROM employee;14 rows deleted.14 rows deleted.SQL> ROLLBACK;Rollback complete.Rollback complete.
Rolling Back Changes to a Marker
Rolling Back Changes to a Marker
Create a marker in a current transaction by using the SAVEPOINT statement.
Roll back to that marker by using the ROLLBACK TO SAVEPOINT statement.
Create 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.Savepoint created.SQL> INSERT...SQL> ROLLBACK TO update_done;Rollback complete.Rollback complete.
Statement-Level RollbackStatement-Level Rollback
If 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.
If 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.
Read ConsistencyRead 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
Read 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
Implementation of Read Consistency
Implementation of Read Consistency
UPDATE empUPDATE empSET sal = 2000SET sal = 2000WHERE ename = WHERE ename = 'SCOTT';'SCOTT';
DataDatablocksblocks
RollbackRollbacksegmentssegments
changedchangedand and unchanged unchanged datadata
before before changechange“old” data“old” data
User AUser A
User BUser B
ReadReadconsistentconsistentimageimage
SELECT *SELECT *FROMFROM emp;emp;