Toad For Oracle 12 Tutorial
I just start working on oracle and using Toad for Oracle but it is not as simple to use any good,simple and easy reference material/manual/tutorial or how to use Toad for oracle efficiently? Particularly I am using Toad for Oracle 10.6
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Toad for Oracle - Any good tutorial for beginners? On oracle and using Toad for Oracle but it is not as simple to use any good,simple and easy reference material/manual/tutorial or how to use Toad for oracle efficiently? Closed as off-topic by Ken White.
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1 Answer
ToadForOracle.com redirects to ToadWorld here:http://www.toadworld.com/products/toad-for-oracle/default.aspxThe getting-started videos provide orientation.The user guide (this one specific to v11.6) is here:http://documents.quest.com/Toad%20for%20Oracle/11.6.1/User%20Guide/to view online, or download the pdf in the top-right corner.Regards,DonnaTfO tech-writer
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This chapter contains:
About Triggers
A trigger is a PL/SQL unit that is stored in the database and (if it is in the enabled state) automatically executes ('fires') in response to a specified event.
A trigger has this structure:
The trigger_name
must be unique for triggers in the schema. A trigger can have the same name as another kind of object in the schema (for example, a table); however, Oracle recommends using a naming convention that avoids confusion.
If the trigger is in the enabled state, the triggering_event
causes the database to execute the triggered_action
if the trigger_restriction
is either TRUE
or omitted. The triggering_event
is associated with either a table, a view, a schema, or the database, and it is one of these:
DML statement (described in 'About Data Manipulation Language (DML) Statements')
DDL statement (described in 'About Data Definition Language (DDL) Statements')
Database operation (
SERVERERROR
,LOGON
,LOGOFF
,STARTUP
, orSHUTDOWN
)
If the trigger is in the disabled state, the triggering_event
does not cause the database to execute the triggered_action
, even if the trigger_restriction
is TRUE
or omitted.
By default, a trigger is created in the enabled state. You can disable an enabled trigger, and enable a disabled trigger.
Unlike a subprogram, a trigger cannot be invoked directly. A trigger is invoked only by its triggering event, which can be caused by any user or application. You might be unaware that a trigger is executing unless it causes an error that is not handled properly.
A simple trigger can fire at exactly one of these timing points:
Before the triggering event executes (statement-level
BEFORE
trigger)After the triggering event executes (statement-level
AFTER
trigger)Before each row that the event affects (row-level
BEFORE
trigger)After each row that the event affects (row-level
AFTER
trigger)
A compound trigger can fire at multiple timing points. For information about compound triggers, see Oracle Database PL/SQL Language Reference.
An INSTEAD
OF
trigger is defined on a view, and its triggering event is a DML statement. Instead of executing the DML statement, Oracle Database executes the INSTEAD
OF
trigger. For more information, see 'Creating an INSTEAD OF Trigger'.
A system trigger is defined on a schema or the database. A trigger defined on a schema fires for each event associated with the owner of the schema (the current user). A trigger defined on a database fires for each event associated with all users.
One use of triggers is to enforce business rules that apply to all client applications. For example, suppose that data added to the EMPLOYEES
table must have a certain format, and that many client applications can add data to this table. A trigger on the table can ensure the proper format of all data added to it. Because the trigger executes whenever any client adds data to the table, no client can circumvent the rules, and the code that enforces the rules can be stored and maintained only in the trigger, rather than in every client application. For other uses of triggers, see Oracle Database PL/SQL Language Reference.
See Also:
Oracle Database PL/SQL Language Reference for complete information about triggersToad For Oracle Download
Creating Triggers
To create triggers, use either the SQL Developer tool Create Trigger or the DDL statement CREATE
TRIGGER
. This section shows how to use both of these ways to create triggers.
By default, a trigger is created in the enabled state. To create a trigger in disabled state, use the CREATE
TRIGGER
statement with the DISABLE
clause.
Note:
To create triggers, you must have appropriate privileges; however, for this discussion, you do not need this additional information.This section contains:
Note:
Toad For Oracle Freeware
To do the tutorials in this document, you must be connected to Oracle Database as the userHR
from SQL Developer.See Also:
Oracle SQL Developer User's Guide for information about SQL Developer dialog boxes for creating objects
Oracle Database PL/SQL Language Reference for more information about the
CREATE
TRIGGER
statement
About OLD and NEW Pseudorecords
When a row-level trigger fires, the PL/SQL runtime system creates and populates the two pseudorecords OLD
and NEW
. They are called pseudorecords because they have some, but not all, of the properties of records.
For the row that the trigger is processing:
For an
INSERT
trigger,OLD
contains no values, andNEW
contains the new values.For an
UPDATE
trigger,OLD
contains the old values, andNEW
contains the new values.For a
DELETE
trigger,OLD
contains the old values, andNEW
contains no values.
To reference a pseudorecord, put a colon before its name—:OLD
or :NEW
—as in Example 6-1.
See Also:
Oracle Database PL/SQL Language Reference for more information aboutOLD
and NEW
pseudorecordsTutorial: Creating a Trigger that Logs Table Changes
This tutorial shows how to use the CREATE
TRIGGER
statement to create a trigger, EVAL_CHANGE_TRIGGER
, which adds a row to the table EVALUATIONS_LOG
whenever an INSERT
, UPDATE
, or DELETE
statement changes the EVALUATIONS
table.
The trigger adds the row after the triggering statement executes, and uses the conditional predicatesINSERTING
, UPDATING
, and DELETING
to determine which of the three possible DML statements fired the trigger.
EVAL_CHANGE_TRIGGER
is a statement-level trigger and an AFTER trigger.
To create EVALUATIONS_LOG and EVAL_CHANGE_TRIGGER:
Create the
EVALUATIONS_LOG
table:Create
EVAL_CHANGE_TRIGGER
:
See Also:
Oracle Database PL/SQL Language Reference for more information about conditional predicatesTutorial: Creating a Trigger that Generates a Primary Key for a Row Before It Is Inserted
The sequence EVALUATIONS_SEQUENCE
(created in 'Tutorial: Creating a Sequence') generates primary keys for the EVALUATIONS
table (created in 'Creating Tables'). However, these primary keys are not inserted into the table automatically.
This tutorial shows how to use the SQL Developer Create Trigger tool to create a trigger named NEW_EVALUATION_TRIGGER
, which fires before a row is inserted into the EVALUATIONS
table, and generates the unique number for the primary key of that row, using EVALUATIONS_SEQUENCE
. The trigger fires once for each row affected by the triggering INSERT
statement.
NEW_EVALUATION_TRIGGER
is a row-level trigger and a BEFORE trigger.
To create the NEW_EVALUATION trigger:
In the Connections frame, expand hr_conn.
In the list of schema object types, right-click Triggers.
In the list of choices, click New Trigger.
In the Create Trigger window:
In the Name field, type
NEW_EVALUATION_TRIGGER
over the default valueTRIGGER1
.For Base Object, select
EVALUATIONS
from the menu.Move
INSERT
from Available Events to Selected Events.(Select
INSERT
and click >.)Deselect the option Statement Level.
Click OK.
The
NEW_EVALUATION_TRIGGER
pane opens, showing theCREATE
TRIGGER
statement that created the trigger:The title of the
NEW_EVALUATION_TRIGGER
pane is in italic font, indicating that the trigger is not yet saved in the database.
In the
CREATE
TRIGGER
statement, replaceNULL
with this:From the File menu, select Save.
Oracle Database compiles the procedure and saves it. The title of the
NEW_EVALUATION_TRIGGER
pane is no longer in italic font.
Creating an INSTEAD OF Trigger
A view presents the output of a query as a table. If you want to change a view as you would change a table, then you must create INSTEAD
OF
triggers. Instead of changing the view, they change the underlying tables.
For example, consider the view EMP_LOCATIONS
, whose NAME
column is created from the LAST_NAME
and FIRST_NAME
columns of the EMPLOYEES
table:
To update the view EMP_LOCATIONS
.NAME
(created in 'Creating Views with the CREATE VIEW Statement'), you must update EMPLOYEES
.LAST_NAME
and EMPLOYEES
.FIRST_NAME
. This is what the INSTEAD
OF
trigger in Example 6-1 does.
NEW
and OLD
are pseudorecords that the PL/SQL runtime engine creates and populates whenever a row-level trigger fires. OLD
and NEW
store the original and new values, respectively, of the record being processed by the trigger. They are called pseudorecords because they do not have all properties of PL/SQL records.
See Also:
Oracle Database PL/SQL Language Reference for more information about
INSTEAD
OF
triggersOracle Database PL/SQL Language Reference for more information about
OLD
andNEW
Tutorial: Creating Triggers that Log LOGON and LOGOFF Events
This tutorial shows how to use the CREATE
TRIGGER
statement to create two triggers, HR_LOGON_TRIGGER
and HR_LOGOFF_TRIGGER
. After someone logs on as user HR
, HR_LOGON_TRIGGER
adds a row to the table HR_USERS_LOG
. Before someone logs off as user HR
, HR_LOGOFF_TRIGGER
adds a row to the table HR_USERS_LOG
.
HR_LOGON_TRIGGER
and HR_LOGOFF_TRIGGER
are system triggers. HR_LOGON_TRIGGER
is an AFTER trigger and HR_LOGOFF_TRIGGER
is a BEFORE trigger.
To create HR_USERS_LOG, HR_LOGON_TRIGGER, and HR_LOGOFF_TRIGGER:
Create the
HR_USERS_LOG
table:Create
hr_logon_trigger
:Create
hr_logoff_trigger
:
See Also:
Oracle Database PL/SQL Language Reference for more information about system triggersChanging Triggers
To change a trigger, use either the SQL Developer tool Edit or the DDL statement CREATE
TRIGGER
with the OR
REPLACE
clause.
To change a trigger using the Edit tool:
In the Connections frame, expand hr_conn.
In the list of schema object types, expand Triggers.
In the list of triggers, click the trigger to change.
In the frame to the right of the Connections frame, the Code pane appears, showing the code that created the trigger.
The Code pane is in write mode. (Clicking the pencil icon switches the mode from write mode to read only, or the reverse.)
In the Code pane, change the code.
The title of the pane is in italic font, indicating that the change is not yet saved in the database.
From the File menu, select Save.
Oracle Database compiles the trigger and saves it. The title of the pane is no longer in italic font.
See Also:
'About Data Definition Language (DDL) Statements' for general information that applies to the
CREATE
OR
REPLACE
TRIGGER
statementOracle Database PL/SQL Language Reference for more information about the
CREATE
OR
REPLACE
TRIGGER
statement
Disabling and Enabling Triggers
You might need to temporarily disable triggers if they reference objects that are unavailable, or if you must upload a large amount of data without the delay that triggers cause (as in a recovery operation). After the referenced objects become available, or you have finished uploading the data, you can re-enable the triggers.
This section contains:
See Also:
Oracle Database PL/SQL Language Reference for more information about the
ALTER
TRIGGER
statementOracle Database SQL Language Reference for more information about the
ALTER
TABLE
statement
Disabling or Enabling a Single Trigger
To disable or enable a single trigger, use either the Disable Trigger or Enable Trigger tool or the ALTER
TRIGGER
statement with the DISABLE
or ENABLE
clause.
For example, these statements disable and enable the eval_change_trigger
:
To use the Disable Trigger or Enable Trigger tool:
In the Connections frame, expand hr_conn.
In the list of schema object types, expand Triggers.
In the list of triggers, right-click the desired trigger.
In the list of choices, select Disable or Enable.
In the Disable or Enable window, click Apply.
In the Confirmation window, click OK.
Disabling or Enabling All Triggers on a Single Table
To disable or enable all triggers on a specific table, use either the Disable All Triggers or Enable All Triggers tool or the ALTER
TABLE
statement with the DISABLE
ALL
TRIGGERS
or ENABLE
ALL
TRIGGERS
clause.
For example, these statements disable and enable all triggers on the evaluations
table:
To use the Disable All Triggers or Enable All Triggers tool:
In the Connections frame, expand hr_conn.
In the list of schema object types, expand Tables.
In the list of tables, right-click the desired table.
In the list of choices, select Triggers.
In the list of choices, select Disable All or Enable All.
In the Disable All or Enable All window, click Apply.
In the Confirmation window, click OK.
About Trigger Compilation and Dependencies
Running a CREATE
TRIGGER
statement compiles the trigger being created. Type in sinhala. If this compilation causes an error, then the CREATE
TRIGGER
statement fails. To see the compilation errors, use this statement:
Compiled triggers depend on the schema objects on which they are defined. For example, NEW_EVALUATION_TRIGGER
depends on the EVALUATIONS
table:
To see the schema objects on which triggers depend, use this statement:
If an object on which a trigger depends is dropped, or changed such that there is a mismatch between the trigger and the object, then the trigger is invalidated. The next time the trigger is invoked, it is recompiled. To recompile a trigger immediately, use the ALTER
TRIGGER
statement with the COMPILE
clause. For example:
See Also:
Oracle Database PL/SQL Language Reference for more information about trigger compilation and dependenciesDropping Triggers
You must drop a trigger before dropping the objects on which it depends.
To drop a trigger, use either the SQL Developer Connections frame and Drop tool, or the DDL statement DROP
TRIGGER
.
This statement drops the trigger EVAL_CHANGE_TRIGGER
:
To drop a trigger using the Drop tool:
In the Connections frame, expand hr_conn.
In the list of schema object types, expand Triggers.
In the list of triggers, right-click the name of the trigger to drop.
In the list of choices, click Drop Trigger.
In the Drop window, click Apply.
In the Confirmation window, click OK.
See Also:
'About Data Definition Language (DDL) Statements' for general information that applies to the
DROP
TRIGGER
statementOracle Database PL/SQL Language Reference for information about the
DROP
TRIGGER
statement