chapter 5 data manipulation and transaction control

Dr. Chen, Oracle Database System (Oracle) 1

Chapter 5Data Manipulation and

Transaction Control

Jason C. H. Chen, Ph.D.Professor of MIS

School of BusinessGonzaga University

Spokane, WA 99258 [email protected]


Objectives

• Use the INSERT command to add a record to an existing table

• Manage virtual columns in data manipulations• Use quotes in data values• Use a subquery to copy records from an existing

table• Use the UPDATE command to modify the

existing rows of a table• Use substitution variables with an UPDATE

command


Objectives (continued)

• Delete records• Manage transactions with transaction

control commands COMMIT, ROLLBACK, and SAVEPOINT

• Differentiate between a shared lock and an exclusive lock

• Use the SELECT…FOR UPDATE command to create a shared lock


Refresh the Database

• 1. Run the following script file– Start c:\oradata\chapter5\JLDB_Build_5.sql


SQL Components

DDL

DML

DCL

D.B.

ORACLE(SQL Components)

(Create Table structure and insert database)


DDL Commands

• Used to create and modify the structure of database objects– CREATE– ALTER– DROP

• DDL commands execute as soon as they are issued, and do not need to be explicitly saved


DML Commands

• Used to insert, view, and modify database data– INSERT– UPDATE– DELETE– SELECT

• DML commands need to be explicitly saved or rolled back – COMMIT– ROLLBACK– SAVEPOINT


DCL Commands

• Used to control the privileges and security of database objects– GRANT– REVOKE


Security -Granting Table Privileges

• Security is the prevention of unauthorized access to the database. Within an organization, the database administrator determines the types of access various users need for the database.

• Some users might be able to retrieve and update data in the database. Other users might be able to retrieve any data from the database but not make any changes to it. Still other users might be able to access only a portion of the database.


INSERT Command

• Used to add rows to existing tables• Identify the table in the INSERT INTO clause• Specify data in the VALUES clause• Can only add one row at a time to a table• Enclose nonnumeric data in single quotes• If a column list is not provided, a value must be

assigned to each column in the table

Figure 5-2 Syntax of the INSERT command


Your Turn …

• Re-run a new script file not including acctmanager table

SQL> start c:\oradata\chapter5\JLDB_Build_5.sql• You now are able to

– create acctmanager table, and– insert new rows (data value) into the acctmanager

table


Rollback - 1

--*********** ROLLBACK AND COMMIT *********SELECT table_name from user_tables;DESC acctmanager;

Amid Amfirst Amlast AmeDate Amsal Amcomm RegionVARCHAR2(4) VARCHAR2(12) VARCHAR2(12) DATE NUMBER(8,2) NUMBER(7,2) CHAR(2)

Next, CREATE table for acctmanager;


The acctmanaer Table Creation

CREATE TABLE acctmanager(amid CHAR(4), amfirst VARCHAR2(12) NOT NULL, amlast VARCHAR2(12) NOT NULL, amedate DATE DEFAULT SYSDATE, amsal NUMBER(8,2), amcomm NUMBER(7,2) DEFAULT 0, region CHAR(2), CONSTRAINT acctmanager_amid_pk PRIMARY KEY (amid), CONSTRAINT acctmanager_region_ck CHECK (region IN ('N', 'NW', 'NE', 'S', 'SE', 'SW', 'W', 'E')));

Figure 5-1 The ACCTMANAGER table creation

Amid Amfirst Amlast AmeDate Amsal Amcomm RegionVARCHAR2(4) VARCHAR2(12) VARCHAR2(12) DATE NUMBER(8,2) NUMBER(7,2) CHAR(2)


Rollback - 2

--*********** ROLLBACK AND COMMIT *********ROLLBACK;DESC acctmanager;-- TABLE of acctmanager still exists. Why?

-- ***NEXT, INSERT a record into acctmanager TABLE


Inserting New RecordsID Name Employment Date Salary Commission RegionT500 Nick Taylor September 5, 2009 $42,000 $3,500 NE

L500 Mandy Lopez October 1, 2009 $47,000 $1,500

J500 Sammie Jones Today $39,5000 $2,000 NW

Table 5-2 Data for Account Managers

Type the following commands:-- chapter 5, Figure 5-3; p. 144INSERT INTO acctmanagerVALUES ('T500', 'NICK', 'TAYLOR', '05-SEP-09', 42000, 3500, 'NE');

SELECT * FROM acctmanager;

amid amfirst amlast ameDate amsal amcomm regionVARCHAR2(4) VARCHAR2(12) VARCHAR2(12) DATE NUMBER(8,2) NUMBER(7,2) CHAR(2)


Rollback - 3

Now a record is inserted into the acctmanager TABLE

--*********** ROLLBACK AND COMMIT *********ROLLBACK;

DESC acctmanager;

-- acctmanager TABLE exists


-- NO data is saved in acctmanager TABLE


Now, Commit and Rollback - 4-- chapter 5, Figure 5-3; p. 144INSERT INTO acctmanagerVALUES ('T500', 'NICK', 'TAYLOR', '05-SEP-09', 42000, 3500, 'NE');


COMMIT;--*********** ROLLBACK AND COMMIT *********ROLLBACK;DESC acctmanager; -- acctmanager TABLE exists

SELECT * FROM acctmanager;The data is still available in acctmanager TABLE


Inserting New Records (Your Turn …)-- chapter 5, Figure 5-5; p. 146INSERT INTO acctmanager (amid, amfirst, amlast, amedate, amsal, amcomm)VALUES ('L500', 'MANDY', 'LOPEZ', '01-OCT-09', 47000, 1500); SELECT *FROM acctmanager;

-- chapter 5, Figure 5-9 (w/different versions); p. 148 [ ERROR OCCURS – why?]INSERT INTO acctmanager (amid, amfirst, amlast, amedate, amsal, amcomm, region)VALUES ('J500', 'Sammie', 'Jones', ‘DEFAULT’, 39500, 2000, 'NW');--[ ERROR OCCURS – (NO ' ')]-- the following two versions are correctINSERT INTO acctmanager (amid, amfirst, amlast, amedate, amsal, amcomm, region)VALUES ('J500', 'Sammie', 'Jones', DEFAULT, 39500, 2000, 'NW');-- orINSERT INTO acctmanager (amid, amfirst, amlast, amsal, amcomm, region)VALUES ('J500', 'Sammie', 'Jones', 39500, 2000, 'NW');-- chapter 5, Figure 5-10; p. 148SELECT *FROM acctmanager;


INSERT Command Examples

No Column List

Column List

Figure 5-3 The INSERT command for Nick Taylor

Figure 5-9 Use an INSERT statement that applies a DEFAULT column option


Three Ways Inserting NULL Value• Omit column name from INSERT INTO clause column list• Substitute two single quotation marks• Use NULL keyword

NULL value inputFigure 5-6 The INSERT INTO command for Mandy Lopez

-- chapter 5, Figure 5-5; p. 146INSERT INTO acctmanager (amid, amfirst, amlast, amedate, amsal, amcomm)VALUES ('L500', 'MANDY', 'LOPEZ', '01-OCT-09', 47000, 1500);

INSERT INTO acctmanagerVALUES ('L500', 'MANDY', 'LOPEZ', '01-OCT-09', 47000, 1500, '');

INSERT INTO acctmanagerVALUES ('L500', 'MANDY', 'LOPEZ', '01-OCT-09', 47000, 1500, NULL);

Run script file on SQL PLUS

NULL value input


Three Ways Inserting “SYSDATE” Value (p.147)

-- chapter 5, Figure 5-9; p. 148INSERT INTO acctmanager (amid, amfirst, amlast, amsal, amcomm, region)VALUES ('J500', 'Sammie', 'Jones', 39500, 2000, 'NW');

• Insert the current date ‘SYSDATE’ in the Amedate column• Use the keyword ‘DEFAULT’ for the column value in the VALUES

clause• Include a column list in the INSERT INTO clause that omits the

Amedate column-- chapter 5, Figure 5-7; 5-8; p. 147-- note that no ‘ ‘ is required, or, error occurredINSERT INTO acctmanager (amid, amfirst, amlast, amedate, amsal, amcomm, region)VALUES ('J500', 'Sammie', 'Jones', SYSDATE, 39500, 2000, 'NW');-- or INSERT INTO acctmanager (amid, amfirst, amlast, amedate, amsal, amcomm, region)VALUES ('J500', 'Sammie', 'Jones', DEFAULT, 39500, 2000, 'NW');


DEFAULT … ON NULL Option (p.149)

Figure 5-11 Using the ON NULL Clauses with a column DEFAULT option

A DEAFULT column option setting will be overridden when an explicit NULL value is inserted. Oracle12c provides an (new) ON NULL clause that may be used with the DEFAULT option.1. Originally, both amedate and amsal are set to NULL (DEFAULT).2. Next, amsal column is further modified to include a DEFAULT option using ON NULL clause, which will set the column value to zero.


Data Dictionary• The data dictionary will assist in identifying information

regarding DEFAULT value settings.

-- chapter 5, Figure 5-12; p. 150SELECT table_name, column_name, data_default, default_on_nullFROM user_tab_columnsWHERE table_name = 'ACCTMANAGER';

UPPER CASE


Handling Virtual Columns

-- chapter 5, Figure 5-13; p. 150ALTER TABLE acctmanagerADD (amearn AS (amsal + amcomm));

-- chapter 5, Figure 5-10; p. 148SELECT *FROM acctmanager;


Create an amearn (acct manager’s earn) column as indicated in Fig. 5-13 (also in Fig. 3-2; p. 64. The column is called “virtual column” (or derived/computed), which is generated from other column values.


Handling Virtual Columns (cont.)

-- chapter 5, Figure 5-14; p. 151SELECT *FROM acctmanager; virtual (derived)

column


Handling Virtual Columns (cont.) - INSERT

-- chapter 5, Figure 5-15; p. 151INSERT INTO acctmanager (amid, amfirst, amlast, amsal, amcomm, region, amearn)VALUES ('D500', 'SCOTT', 'DAVIS', 53000, 6000, 'SE', 59000);

An INSERT attempt of a fourth account manager including a value of virtual column amearn. An error occurs that a value can’t be inserted in a virtual column.

Summary: a virtual column is created and saved permanently in the database. However, the value is added automatically.


Handling Virtual Columns (cont.) - UPDATE

Q: If a value is changed (updated) on the “field(s)” (e.g., amsal change to 40000 on T500) that derive the value on the virtual column, will the value on the virtual column be updated automatically?

UPDATE acctmanagerSET amsal = 40000WHERE amid = 'T500';


What will be new value for amearn on T500?


Handling Virtual Columns (cont.) - UPDATE

Q: If a value is changed (updated) on the “field(s)” (e.g., amsal change to 40000 on T500) that derive the value on the virtual column, will the value on the virtual column be updated automatically?

UPDATE acctmanagerSET amsal = 40000WHERE amid = 'T500';


YES


Handling Single Quotes in an INSERT Value

-- chapter 5, Figure 5-17; p. 152INSERT INTO acctmanager (amid, amfirst, amlast, amsal, amcomm, region)VALUES ('M500', 'Peg', 'O'hara', 46000, 2000, 'SW');

-- chapter 5, Figure 5-18; p. 152 (w two single quotes)INSERT INTO acctmanager (amid, amfirst, amlast, amsal, amcomm, region)VALUES ('M500', 'Peg', 'O''hara', 46000, 2000, 'SW');



Constraint Violations

• When you add or modify table data, the data is checked for compliance with any applicable constraints

• You should practice all examples (more commands such as UPDATE on p.156-163)


Inserting Data from an Existing Table

• Substitute subquery for VALUES clause• Note: make sure you have re-run a new script

file (i.e., JLDB_Build_5.sql) with acctbonus table created.

Subquery

Figure 5-19 INSERT INTO command with a subquery-- chapter 5, Figure 5-20; p. 154SELECT *FROM acctbonus;


Modifying Existing Rows

• Modify rows using UPDATE command• Use UPDATE command to:

– Add values to an existing row (replace NULL values)

– Change existing values• UPDATE clause identifies table• SET clause identifies column(s) being changed and

new value(s)• Optional WHERE clause specifies row(s) to be

changed – if omitted, all rows will be updated!


UPDATE Command Syntax

UPDATE Command ExamplesFigure 5-21 Syntax of the UPDATE command

-- chapter 5, Figure 5-24; p. 157UPDATE acctmanagerSET amedate = '01-AUG-09'WHERE amid = 'J500';-- chapter 5, Figure 5-25; p. 157UPDATE acctmanagerSET region = 'W'WHERE region IN ('NE', 'NW');

-- chapter 5, Figure 5-26; p. 158UPDATE acctmanagerSET amedate = '10-OCT-09', region = 'S'WHERE amid = 'L500';



Substitution Variables

• Prompts user for value• Identified by ampersand (&) preceding

variable name • Can be used to create interactive scripts

-- chapter 5, Figure 5-28; p. 159UPDATE customers SET region = 'W' WHERE state = 'CA';

-- chapter 5, Figure 5-29; p. 160UPDATE customersSET region = '&Region'WHERE state = '&State';


Substitution Variable Example

Figure 5-29 Prompt for substitution variable input


Figure 5-28 Verify UPDATE results


Deleting Rows

• DELETE command removes a row from a table

WHERE clause determines which row(s) are removed

Figure 5-31 DELETE command to remove a row from the ACCTMANAGER table


DELETE Command – Omitting WHERE Clause

• Omitting WHERE clause removes all rows• Example below removes all rows from the

acctmanager table

Figure 5-32 DELETE command without the WHERE clause

Note that you need to have “TWO” DELETE for HW #9 (p.177)


Transaction Control Statements

• Results of data manipulation language (DML) are not permanently updated to a table until explicit or implicit COMMIT occurs

• Transaction control statements can:– Commit data through COMMIT command– Undo data changes through ROLLBACK

command


COMMIT Command

• Explicit COMMIT occurs by executing COMMIT;

• Implicit COMMIT occurs when DDL command is executed or user properly exits system

• Permanently updates table(s) and allows other users to view changes


Transaction Control Example

Figure 5-36 Establishing a SAVEPOINT

A

B

C

ROLLBACK TO ONE;SAVEPOINT ALEX;

UPPLER CASE


Transaction Control Example (continued)

Only undo DML actions after SAVEPOINT

Figure 5-37 Undo changes to SAVEPOINT ONE

-- chapter 5, Figure 5-37; p. 166ROLLBACK TO ONE;

Figure 5-37 Database before using ROLLBACK TO ONE;


Transaction Control Example (continued)

-- chapter 5, Figure 5-38; p. 162ROLLBACK;

Figure 5-39 Verify the ROLLBACK results

Figure 5-37 Database before using ROLLBACK


• Practice all the examples in the text.• A Script file is available on the Bb (file

name: Ch5Queries.sql)• After completing all examples, do the HW.


Homework - Hands-On Assignments

Read and Practice all examples on Chapters 5• 1. Run the script files (in the folder \oradata\

chapter5\): JLDB_Build_5.sql• 2. Read Oracle assignment and create a script file

Oracle_ch5_Lname_Fname.sql for questions (#1 to #5, #9,#10; p.176-177) on “Hands-on Assignments”. .

• 3. Execute and test one problem at a time and make sure they are all running successfully.

• 4. When you done, spool the script files (see next slide for spooling instructions) and UPLOAD the file (Oracle_ch5_Spool_Lname_Fname.txt) to Bb by the midnight before the next class.

Upload the spooled file (*.txt) to the Bb (under “Assignments & Projects”) by the deadline.


How to Spool your Script and Output FilesAfter you tested the script file of Oracle_ch5_Lname_Fname.sql successfully,

follow the instructions below to spool both script and output files:Step 0. Run the following script file from SQL*Plus (since you have created

JLDB tables)– Start c:\oradata\chapter5\JLDB_Build_5.sql

• 1. type the following on SQL>– Spool c:\oradata\Oracle_ch5_Spool_Lname_Fname.txt (make sure your name is entered)

• 2. open Oracle_ch5_Lname_Fname.sql that you already tested• 3. copy and paste all the SQL commands (including all comments) to the

SQL*PLUS • 4. type Spool Off on the SQL>The output should contain your personal information, all SQL commands and

their solution on the .txt file and saved in C: drive (oradata\ folder)

Upload the spooled file (*.txt) to the Bb (under “Assignments & Projects”) by the deadline.


Summary

• Data manipulation language (DML) includes the INSERT, UPDATE, DELETE, COMMIT, and ROLLBACK commands

• The INSERT INTO command is used to add new rows to an existing table

• The column list specified in the INSERT INTO clause must match the order of data entered in the VALUES clause

• A virtual column must be ignored in all DML actions because the database system generates this column value automatically

• You can use a NULL value in an INSERT INTO command by including the keyword NULL, omitting the column from the column list of the INSERT INTO clause, or entering two single quotes (without a space) in the position of the NULL value


Summary (continued)• To assign a DEFAULT option value, a column must be

excluded from the column list in an INSERT statement or the keyword DEFAULT must be included as the value for the column

• In a DML statement, two single quotes together must be used to represent a single quote in a value

• If rows are copied from a table and entered in an existing table by using a subquery in the INSERT INTO command, the VALUES clause must be omitted because it’s irrelevant

• You can change the contents of a row or group of rows with the UPDATE command

• You can use substitution variables to allow you to execute the same command several times with different data values


Summary (continued)

• DML operations aren’t stored permanently in a table until a COMMIT command is issued implicitly or explicitly

• A transaction consists of a set of DML operations committed as a block

• Uncommitted DML operations can be undone by issuing the ROLLBACK command

• A SAVEPOINT serves as a marker for a point in a transaction and allows rolling back only a portion of the transaction

• Use the DELETE command to remove records from a table; if the WHERE clause is omitted, all rows in the table are deleted

• Table locks can be used to prevent users from mistakenly overwriting changes made by other users


Summary (continued)• Table locks can be in SHARE mode or EXCLUSIVE mode• EXCLUSIVE mode is the most restrictive table lock and

prevents any other user from placing any locks on the same table

• A lock is released when a transaction control statement is issued, a DDL statement is executed, or the user exits the system by using the EXIT command

• SHARE mode allows other users to place shared locks on other portions of the table, but it prevents users from placing an exclusive lock on the table

• The SELECT . . . FOR UPDATE command can be used to place a shared lock for a specific row or rows; the lock isn’t released unless a DDL command is issued or the user exits the system


End of Chapter 5

chapter 5 data manipulation and transaction control

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