06 ICT118 SQL Txn Control Sem 2 2010

8/2/2019 06 ICT118 SQL Txn Control Sem 2 2010

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Database and InformationDatabase and InformationDatabase and InformationDatabase and Information

RetrievalRetrievalRetrievalRetrieval

ICT118

Lecture 6 Adding data to tables TransactionControl syntax

22 July, 2010 ICT118 Database and Information Retrieval, Sem 2, 2010 6.2

Oracle 11g: SQL

Chapter 5

Data Manipulation and Transaction ControlSlides from Cengage website for Casteel, Oracle 11g:SQL


ObjectivesObjectivesObjectivesObjectives

Use the INSERT command to add a record to anUse the INSERT command to add a record to anUse the INSERT command to add a record to anUse the INSERT command to add a record to anexisting tableexisting tableexisting tableexisting table

Manage virtual columns in data manipulationsManage virtual columns in data manipulationsManage virtual columns in data manipulationsManage virtual columns in data manipulations

Use quotes in data valuesUse quotes in data valuesUse quotes in data valuesUse quotes in data values

Use a subquery to copy records from an existingUse a subquery to copy records from an existingUse a subquery to copy records from an existingUse a subquery to copy records from an existingtabletabletabletable

Use the UPDATE command to modify the existingUse the UPDATE command to modify the existingUse the UPDATE command to modify the existingUse the UPDATE command to modify the existingrows of a tablerows of a tablerows of a tablerows of a table

Use substitution variables with an UPDATEUse substitution variables with an UPDATEUse substitution variables with an UPDATEUse substitution variables with an UPDATEcommandcommandcommandcommand


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Objectives (continued)Objectives (continued)Objectives (continued)Objectives (continued)

Delete recordsDelete recordsDelete recordsDelete records

Manage transactions with transaction controlManage transactions with transaction controlManage transactions with transaction controlManage transactions with transaction controlcommands COMMIT, ROLLBACK, andcommands COMMIT, ROLLBACK, andcommands COMMIT, ROLLBACK, andcommands COMMIT, ROLLBACK, andSAVEPOINTSAVEPOINTSAVEPOINTSAVEPOINT

Differentiate between a shared lock and anDifferentiate between a shared lock and anDifferentiate between a shared lock and anDifferentiate between a shared lock and anexclusive lockexclusive lockexclusive lockexclusive lock

Use the SELECTFOR UPDATE command toUse the SELECTFOR UPDATE command toUse the SELECTFOR UPDATE command toUse the SELECTFOR UPDATE command tocreate a shared lockcreate a shared lockcreate a shared lockcreate a shared lock


INSERT CommandINSERT CommandINSERT CommandINSERT Command

Used to add rows to existing tablesUsed to add rows to existing tablesUsed to add rows to existing tablesUsed to add rows to existing tables

Identify the table in the INSERT INTO clauseIdentify the table in the INSERT INTO clauseIdentify the table in the INSERT INTO clauseIdentify the table in the INSERT INTO clause

Specify data in the VALUES clauseSpecify data in the VALUES clauseSpecify data in the VALUES clauseSpecify data in the VALUES clause

Can only add one row at a time to a tableCan only add one row at a time to a tableCan only add one row at a time to a tableCan only add one row at a time to a table


INSERT Command SyntaxINSERT Command SyntaxINSERT Command SyntaxINSERT Command Syntax

Enclose nonEnclose nonEnclose nonEnclose non----numeric data in singlenumeric data in singlenumeric data in singlenumeric data in single

quotesquotesquotesquotes

If a column list is not provided, a valueIf a column list is not provided, a valueIf a column list is not provided, a valueIf a column list is not provided, a value

must be assigned to each column in themust be assigned to each column in themust be assigned to each column in themust be assigned to each column in the

tabletabletabletable


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INSERT Command ExamplesINSERT Command ExamplesINSERT Command ExamplesINSERT Command ExamplesNo Column List

Column List


Inserting NULL ValueInserting NULL ValueInserting NULL ValueInserting NULL Value

Omit column name from INSERT INTOOmit column name from INSERT INTOOmit column name from INSERT INTOOmit column name from INSERT INTO

clause column listclause column listclause column listclause column list

Substitute two single quotation marks orSubstitute two single quotation marks orSubstitute two single quotation marks orSubstitute two single quotation marks or

Use NULL keywordUse NULL keywordUse NULL keywordUse NULL keyword

NULL value input


Manage Virtual Column InputManage Virtual Column InputManage Virtual Column InputManage Virtual Column Input


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Constraint ViolationsConstraint ViolationsConstraint ViolationsConstraint Violations

When you add or modify table data, the data isWhen you add or modify table data, the data isWhen you add or modify table data, the data isWhen you add or modify table data, the data is

checked for compliance with any applicablechecked for compliance with any applicablechecked for compliance with any applicablechecked for compliance with any applicable

constraintsconstraintsconstraintsconstraints


Activating the DEFAULT optionActivating the DEFAULT optionActivating the DEFAULT optionActivating the DEFAULT option

Include a column list in the INSERT statementInclude a column list in the INSERT statementInclude a column list in the INSERT statementInclude a column list in the INSERT statement

ignoring the column to use the DEFAULTignoring the column to use the DEFAULTignoring the column to use the DEFAULTignoring the column to use the DEFAULT

optionoptionoptionoption

Use the DEFAULT keyword as the value for theUse the DEFAULT keyword as the value for theUse the DEFAULT keyword as the value for theUse the DEFAULT keyword as the value for the

columncolumncolumncolumn


Inserting Data from an ExistingInserting Data from an ExistingInserting Data from an ExistingInserting Data from an Existing

TableTableTableTable

Substitute subquery for VALUES clauseSubstitute subquery for VALUES clauseSubstitute subquery for VALUES clauseSubstitute subquery for VALUES clause

Subquery


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Modifying Existing RowsModifying Existing RowsModifying Existing RowsModifying Existing Rows

Modify rows using UPDATE commandModify rows using UPDATE commandModify rows using UPDATE commandModify rows using UPDATE command

Use UPDATE command to:Use UPDATE command to:Use UPDATE command to:Use UPDATE command to:

Add values to an existing row (replace NULL

values)

Change existing values


UPDATE CommandUPDATE CommandUPDATE CommandUPDATE Command

UPDATE clause identifies tableUPDATE clause identifies tableUPDATE clause identifies tableUPDATE clause identifies table

SET clause identifies column(s) being changedSET clause identifies column(s) being changedSET clause identifies column(s) being changedSET clause identifies column(s) being changed

and new value(s)and new value(s)and new value(s)and new value(s)

Optional WHERE clause specifies row(s) to beOptional WHERE clause specifies row(s) to beOptional WHERE clause specifies row(s) to beOptional WHERE clause specifies row(s) to be

changedchangedchangedchanged if omitted, all rows will beif omitted, all rows will beif omitted, all rows will beif omitted, all rows will be

updated!updated!updated!updated!


UPDATE Command SyntaxUPDATE Command SyntaxUPDATE Command SyntaxUPDATE Command Syntax


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UPDATE Command ExampleUPDATE Command ExampleUPDATE Command ExampleUPDATE Command Example


Substitution VariablesSubstitution VariablesSubstitution VariablesSubstitution Variables

Prompts user for valuePrompts user for valuePrompts user for valuePrompts user for value

Identified by ampersand (&) preceding aIdentified by ampersand (&) preceding aIdentified by ampersand (&) preceding aIdentified by ampersand (&) preceding a

variable namevariable namevariable namevariable name

Can be used to create interactive scriptsCan be used to create interactive scriptsCan be used to create interactive scriptsCan be used to create interactive scripts


Substitution Variable ExampleSubstitution Variable ExampleSubstitution Variable ExampleSubstitution Variable Example


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Deleting RowsDeleting RowsDeleting RowsDeleting Rows

DELETE command removes a row from aDELETE command removes a row from aDELETE command removes a row from aDELETE command removes a row from atabletabletabletable

WHERE clause

determines which

row(s) are removed


DELETE CommandDELETE CommandDELETE CommandDELETE Command OmittingOmittingOmittingOmitting

WHERE ClauseWHERE ClauseWHERE ClauseWHERE Clause

Omitting the WHERE clause removesOmitting the WHERE clause removesOmitting the WHERE clause removesOmitting the WHERE clause removes allallallall rowsrowsrowsrows

Example below removes all rows from theExample below removes all rows from theExample below removes all rows from theExample below removes all rows from theacctmanager tableacctmanager tableacctmanager tableacctmanager table


Transaction Control StatementsTransaction Control StatementsTransaction Control StatementsTransaction Control Statements

Results of data manipulation language (DML)Results of data manipulation language (DML)Results of data manipulation language (DML)Results of data manipulation language (DML)

are not permanently updated to a table untilare not permanently updated to a table untilare not permanently updated to a table untilare not permanently updated to a table until

explicit or implicit COMMIT occursexplicit or implicit COMMIT occursexplicit or implicit COMMIT occursexplicit or implicit COMMIT occurs

Transaction control statements can:Transaction control statements can:Transaction control statements can:Transaction control statements can:

Commit data through COMMIT command

Undo data changes through ROLLBACK command


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COMMIT CommandCOMMIT CommandCOMMIT CommandCOMMIT Command

Explicit COMMIT occurs by executing COMMIT;Explicit COMMIT occurs by executing COMMIT;Explicit COMMIT occurs by executing COMMIT;Explicit COMMIT occurs by executing COMMIT;

Implicit COMMIT occurs when DDL commandImplicit COMMIT occurs when DDL commandImplicit COMMIT occurs when DDL commandImplicit COMMIT occurs when DDL command

is executed or user properly exits systemis executed or user properly exits systemis executed or user properly exits systemis executed or user properly exits system

Permanently updates table(s) and allows otherPermanently updates table(s) and allows otherPermanently updates table(s) and allows otherPermanently updates table(s) and allows other

users to view changesusers to view changesusers to view changesusers to view changes


ROLLBACK CommandROLLBACK CommandROLLBACK CommandROLLBACK Command

Used to undo changes that have not beenUsed to undo changes that have not beenUsed to undo changes that have not beenUsed to undo changes that have not beencommittedcommittedcommittedcommitted

Occurs when:Occurs when:Occurs when:Occurs when:ROLLBACK; is executed

System restarts after a crash

SAVEPOINT marks a specific spot withinSAVEPOINT marks a specific spot withinSAVEPOINT marks a specific spot withinSAVEPOINT marks a specific spot withinthe transactionthe transactionthe transactionthe transaction

Can ROLLBACK to a SAVEPOINT to undoCan ROLLBACK to a SAVEPOINT to undoCan ROLLBACK to a SAVEPOINT to undoCan ROLLBACK to a SAVEPOINT to undopart of the transactionpart of the transactionpart of the transactionpart of the transaction


Transaction Control ExampleTransaction Control ExampleTransaction Control ExampleTransaction Control Example


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Transaction Control ExampleTransaction Control ExampleTransaction Control ExampleTransaction Control Example

(continued)(continued)(continued)(continued)

Only undo DML

actions after

SAVEPOINT


Table LocksTable LocksTable LocksTable Locks

Prevent users from changing same data orPrevent users from changing same data orPrevent users from changing same data orPrevent users from changing same data or

objectsobjectsobjectsobjects

Two typesTwo typesTwo typesTwo types

Shared prevents DML operations on a portion of

table

Exclusive locks table preventing other exclusiveor shared locks


LOCK TABLE CommandLOCK TABLE CommandLOCK TABLE CommandLOCK TABLE Command

Shared LockShared LockShared LockShared Lock

Locks portion of table affected by DMLLocks portion of table affected by DMLLocks portion of table affected by DMLLocks portion of table affected by DMLoperationoperationoperationoperation

Implicitly occurs during UPDATE or DELETEImplicitly occurs during UPDATE or DELETEImplicitly occurs during UPDATE or DELETEImplicitly occurs during UPDATE or DELETEoperationsoperationsoperationsoperations

Explicitly occurs through LOCK TABLEExplicitly occurs through LOCK TABLEExplicitly occurs through LOCK TABLEExplicitly occurs through LOCK TABLEcommand with SHARE MODE optioncommand with SHARE MODE optioncommand with SHARE MODE optioncommand with SHARE MODE option

Released when COMMIT (implicit or explicit) orReleased when COMMIT (implicit or explicit) orReleased when COMMIT (implicit or explicit) orReleased when COMMIT (implicit or explicit) orROLLBACK occursROLLBACK occursROLLBACK occursROLLBACK occurs


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LOCK TABLE CommandLOCK TABLE CommandLOCK TABLE CommandLOCK TABLE Command

Exclusive LockExclusive LockExclusive LockExclusive LockImplicitly locks table for DDL operationsImplicitly locks table for DDL operationsImplicitly locks table for DDL operationsImplicitly locks table for DDL operations

CREATE or ALTER TABLECREATE or ALTER TABLECREATE or ALTER TABLECREATE or ALTER TABLE

Explicitly locked through LOCK TABLEExplicitly locked through LOCK TABLEExplicitly locked through LOCK TABLEExplicitly locked through LOCK TABLE

command with EXCLUSIVE MODE optioncommand with EXCLUSIVE MODE optioncommand with EXCLUSIVE MODE optioncommand with EXCLUSIVE MODE option

Released after execution of DDL operation orReleased after execution of DDL operation orReleased after execution of DDL operation orReleased after execution of DDL operation or

after user exits systemafter user exits systemafter user exits systemafter user exits system


SELECTFOR UPDATESELECTFOR UPDATESELECTFOR UPDATESELECTFOR UPDATE

CommandCommandCommandCommand

Creates shared lock on retrieved portion ofCreates shared lock on retrieved portion ofCreates shared lock on retrieved portion ofCreates shared lock on retrieved portion of

tabletabletabletable

Prevents one user from changing a row whilePrevents one user from changing a row whilePrevents one user from changing a row whilePrevents one user from changing a row while

another user is selecting rows to be changedanother user is selecting rows to be changedanother user is selecting rows to be changedanother user is selecting rows to be changed

Released through implicit or explicit commitReleased through implicit or explicit commitReleased through implicit or explicit commitReleased through implicit or explicit commit


SELECTFOR UPDATESELECTFOR UPDATESELECTFOR UPDATESELECTFOR UPDATECommand SyntaxCommand SyntaxCommand SyntaxCommand Syntax


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SummarySummarySummarySummary

Data manipulation language (DML) includes the INSERT,Data manipulation language (DML) includes the INSERT,Data manipulation language (DML) includes the INSERT,Data manipulation language (DML) includes the INSERT,

UPDATE, DELETE, COMMIT, and ROLLBACKUPDATE, DELETE, COMMIT, and ROLLBACKUPDATE, DELETE, COMMIT, and ROLLBACKUPDATE, DELETE, COMMIT, and ROLLBACKcommandscommandscommandscommands

The INSERT INTO command is used to add new rows to anThe INSERT INTO command is used to add new rows to anThe INSERT INTO command is used to add new rows to anThe INSERT INTO command is used to add new rows to an

existing tableexisting tableexisting tableexisting table

The column list specified in the INSERT INTO clause mustThe column list specified in the INSERT INTO clause mustThe column list specified in the INSERT INTO clause mustThe column list specified in the INSERT INTO clause must

match the order of data entered in the VALUES clausematch the order of data entered in the VALUES clausematch the order of data entered in the VALUES clausematch the order of data entered in the VALUES clause

A virtual column must be ignored in all DML actionsA virtual column must be ignored in all DML actionsA virtual column must be ignored in all DML actionsA virtual column must be ignored in all DML actions

because the database system generates this columnbecause the database system generates this columnbecause the database system generates this columnbecause the database system generates this column

value automaticallyvalue automaticallyvalue automaticallyvalue automatically

You can use a NULL value in an INSERT INTO commandYou can use a NULL value in an INSERT INTO commandYou can use a NULL value in an INSERT INTO commandYou can use a NULL value in an INSERT INTO command

by including the keyword NULL, omitting the columnby including the keyword NULL, omitting the columnby including the keyword NULL, omitting the columnby including the keyword NULL, omitting the column

from the column list of the INSERT INTO clause, orfrom the column list of the INSERT INTO clause, orfrom the column list of the INSERT INTO clause, orfrom the column list of the INSERT INTO clause, or

entering two single quotes (without a space) in theentering two single quotes (without a space) in theentering two single quotes (without a space) in theentering two single quotes (without a space) in the

position of the NULL valueposition of the NULL valueposition of the NULL valueposition of the NULL value


Summary (continued)Summary (continued)Summary (continued)Summary (continued)

To assign a DEFAULT option value, a column must beTo assign a DEFAULT option value, a column must beTo assign a DEFAULT option value, a column must beTo assign a DEFAULT option value, a column must be

excluded from the column list in an INSERT statement orexcluded from the column list in an INSERT statement orexcluded from the column list in an INSERT statement orexcluded from the column list in an INSERT statement or

the keyword DEFAULT must be included as the value for thethe keyword DEFAULT must be included as the value for thethe keyword DEFAULT must be included as the value for thethe keyword DEFAULT must be included as the value for the

columncolumncolumncolumn

In a DML statement, two single quotes together must be usedIn a DML statement, two single quotes together must be usedIn a DML statement, two single quotes together must be usedIn a DML statement, two single quotes together must be used

to represent a single quote in a valueto represent a single quote in a valueto represent a single quote in a valueto represent a single quote in a value

If rows are copied from a table and entered in an existing tableIf rows are copied from a table and entered in an existing tableIf rows are copied from a table and entered in an existing tableIf rows are copied from a table and entered in an existing table

by using a subquery in the INSERT INTO command, theby using a subquery in the INSERT INTO command, theby using a subquery in the INSERT INTO command, theby using a subquery in the INSERT INTO command, the

VALUES clause must be omitted because its irrelevantVALUES clause must be omitted because its irrelevantVALUES clause must be omitted because its irrelevantVALUES clause must be omitted because its irrelevantYou can change the contents of a row or group of rows withYou can change the contents of a row or group of rows withYou can change the contents of a row or group of rows withYou can change the contents of a row or group of rows with

the UPDATE commandthe UPDATE commandthe UPDATE commandthe UPDATE command

You can use substitution variables to allow you to execute theYou can use substitution variables to allow you to execute theYou can use substitution variables to allow you to execute theYou can use substitution variables to allow you to execute the

same command several times with different data valuessame command several times with different data valuessame command several times with different data valuessame command several times with different data values


Summary (continued)Summary (continued)Summary (continued)Summary (continued)DML operations arent stored permanently in a table until aDML operations arent stored permanently in a table until aDML operations arent stored permanently in a table until aDML operations arent stored permanently in a table until a

COMMIT command is issued implicitly or explicitlyCOMMIT command is issued implicitly or explicitlyCOMMIT command is issued implicitly or explicitlyCOMMIT command is issued implicitly or explicitly

A transaction consists of a set of DML operationsA transaction consists of a set of DML operationsA transaction consists of a set of DML operationsA transaction consists of a set of DML operations

committed as a blockcommitted as a blockcommitted as a blockcommitted as a block

Uncommitted DML operations can be undone by issuing theUncommitted DML operations can be undone by issuing theUncommitted DML operations can be undone by issuing theUncommitted DML operations can be undone by issuing the

ROLLBACK commandROLLBACK commandROLLBACK commandROLLBACK command

A SAVEPOINT serves as a marker for a point in aA SAVEPOINT serves as a marker for a point in aA SAVEPOINT serves as a marker for a point in aA SAVEPOINT serves as a marker for a point in a

transaction and allows rolling back only a portion of thetransaction and allows rolling back only a portion of thetransaction and allows rolling back only a portion of thetransaction and allows rolling back only a portion of the

transactiontransactiontransactiontransaction

Use the DELETE command to remove records from a table;Use the DELETE command to remove records from a table;Use the DELETE command to remove records from a table;Use the DELETE command to remove records from a table;

if the WHERE clause is omitted, all rows in the table areif the WHERE clause is omitted, all rows in the table areif the WHERE clause is omitted, all rows in the table areif the WHERE clause is omitted, all rows in the table are

deleteddeleteddeleteddeleted

Table locks can be used to prevent users from mistakenlyTable locks can be used to prevent users from mistakenlyTable locks can be used to prevent users from mistakenlyTable locks can be used to prevent users from mistakenly

overwriting changes made by other usersoverwriting changes made by other usersoverwriting changes made by other usersoverwriting changes made by other users


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Summary (continued)Summary (continued)Summary (continued)Summary (continued)

Table locks can be in SHARE mode or EXCLUSIVE modeTable locks can be in SHARE mode or EXCLUSIVE modeTable locks can be in SHARE mode or EXCLUSIVE modeTable locks can be in SHARE mode or EXCLUSIVE mode

EXCLUSIVE mode is the most restrictive table lock andEXCLUSIVE mode is the most restrictive table lock andEXCLUSIVE mode is the most restrictive table lock andEXCLUSIVE mode is the most restrictive table lock andprevents any other user from placing any locks on theprevents any other user from placing any locks on theprevents any other user from placing any locks on theprevents any other user from placing any locks on the

same tablesame tablesame tablesame table

A lock is released when a transaction control statement isA lock is released when a transaction control statement isA lock is released when a transaction control statement isA lock is released when a transaction control statement is

issued, a DDL statement is executed, or the user exitsissued, a DDL statement is executed, or the user exitsissued, a DDL statement is executed, or the user exitsissued, a DDL statement is executed, or the user exits

the system by using the EXIT commandthe system by using the EXIT commandthe system by using the EXIT commandthe system by using the EXIT command

SHARE mode allows other users to place shared locks onSHARE mode allows other users to place shared locks onSHARE mode allows other users to place shared locks onSHARE mode allows other users to place shared locks on

other portions of the table, but it prevents users fromother portions of the table, but it prevents users fromother portions of the table, but it prevents users fromother portions of the table, but it prevents users from

placing an exclusive lock on the tableplacing an exclusive lock on the tableplacing an exclusive lock on the tableplacing an exclusive lock on the table

The SELECT . . . FOR UPDATE command can be used toThe SELECT . . . FOR UPDATE command can be used toThe SELECT . . . FOR UPDATE command can be used toThe SELECT . . . FOR UPDATE command can be used to

place a shared lock for a specific row or rows; the lockplace a shared lock for a specific row or rows; the lockplace a shared lock for a specific row or rows; the lockplace a shared lock for a specific row or rows; the lock

isnt released unless a DDL command is issued or theisnt released unless a DDL command is issued or theisnt released unless a DDL command is issued or theisnt released unless a DDL command is issued or the

user exits the systemuser exits the systemuser exits the systemuser exits the system

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