Paper 13

17. What is difference between CHAR and VARCHAR2 ? What is the maximum SIZE allowed for each type ?

CHAR pads blank spaces to the maximum length. VARCHAR2 does not pad blank spaces. For CHAR it is 255 and 2000 for VARCHAR2.

18. How many LONG columns are allowed in a table ? Is it possible to use LONG columns in WHERE clause or ORDER BY ?
Only one LONG columns is allowed. It is not possible to use LONG column in WHERE or ORDER BY clause.

19. What are the pre requisites ?
I. to modify datatype of a column ?
ii. to add a column with NOT NULL constraint ?
To Modify the datatype of a column the column must be empty.
to add a column with NOT NULL constrain, the table must be empty.

20. Where the integrity constrints are stored in Data Dictionary ?
The integrity constraints are stored in USER_CONSTRAINTS.

21. How will you a activate/deactivate integrity constraints ?
The integrity constraints can be enabled or disabled by ALTER TABLE ENABLE constraint/DISABLE constraint.

22. If an unique key constraint on DATE column is created, will it validate the rows that are inserted with SYSDATE ?
It won't, Because SYSDATE format contains time attached with it.

23. What is a database link ?
Database Link is a named path through which a remote database can be accessed.

24. How to access the current value and next value from a sequence ? Is it possible to access the current value in a session before accessing next value ?
Sequence name CURRVAL, Sequence name NEXTVAL.
It is not possible. Only if you access next value in the session, current value can be accessed.

25. What is CYCLE/NO CYCLE in a Sequence ?
CYCLE specifies that the sequence continues to generate values after reaching either maximum or minimum value. After pan ascending sequence reaches its maximum value, it generates its minimum value. After a descending sequence reaches its minimum, it generates its maximum.
NO CYCLE specifies that the sequence cannot generate more values after reaching its maximum or minimum value.

26. What are the advantages of VIEW ?

To protect some of the columns of a table from other users.
To hide complexity of a query.
To hide complexity of calculations.

27. Can a view be updated/inserted/deleted? If Yes under what conditions ?
A View can be updated/deleted/inserted if it has only one base table if the view is based on columns from one or more tables then insert, update and delete is not possible.

28.If a View on a single base table is manipulated will the changes be reflected on the base table ?
If changes are made to the tables which are base tables of a view will the changes be reference on the view.


FORMS 3.0 BASIC
1.What is an SQL *FORMS ?

SQL *forms is 4GL tool for developing and executing; Oracle based interactive application.

2. What is the maximum size of a form ?
255 character width and 255 characters Length.

3. Name the two files that are created when you generate the form give the filex extension ?
INP (Source File)
FRM (Executable File)

4. How do you control the constraints in forms ?
Select the use constraint property is ON Block definition screen.

BLOCK
5. Commited block sometimes refer to a BASE TABLE ? True or False.
False.

6. Can we create two blocks with the same name in form 3.0 ?
No.

7. While specifying master/detail relationship between two blocks specifying the join condition is a must ? True or False.
True.

8. What is a Trigger ?
A piece of logic that is executed at or triggered by a SQL *forms event.


9. What are the types of TRIGGERS ?
1. Navigational Triggers.
2. Transaction Triggers.

10. What are the different types of key triggers ?
Function Key
Key-function
Key-others
Key-startup

11. What is the difference between a Function Key Trigger and Key Function Trigger ?
Function key triggers are associated with individual SQL*FORMS function keys
You can attach Key function triggers to 10 keys or key sequences that normally do not perform any SQL * FORMS operations. These keys refered as key F0 through key F9.

12. What does an on-clear-block Trigger fire?
It fires just before SQL * forms the current block.

13. How do you trap the error in forms 3.0 ?
using On-Message or On-Error triggers.

14. State the order in which these triggers are executed ?

POST-FIELD,ON-VALIDATE-FIELD,POST-CHANGE and KEY-NEXTFLD.
KEY-NEXTFLD,POST-CHANGE, ON-VALIDATE-FIELD, POST-FIELD.

15. What is the usuage of an ON-INSERT,ON-DELETE and ON-UPDATE TRIGGERS ?

These triggers are executes when inserting,deleting and updating operations are performed and can be used to change the default function of insert,delete or update respectively.

For Eg, instead of inserting a row in a table an existing row can be updated in the same table.

16. When will ON-VALIDATE-FIELD trigger executed ?
It fires when a value in a field has been changed and the field status is changed or new and the key has been pressed. If the field status is valid then any further change to the value in the field will not fire the on-validate-field trigger.

17. A query fetched 10 records How many times does a PRE-QUERY Trigger and POST-QUERY Trigger will get executed ?

PRE-QUERY fires once.
POST-QUERY fires 10 times.

18. What is the difference between ON-VALIDATE-FIELD trigger and a POST-CHANGE trigger ?
When you changes the Existing value to null, the On-validate field trigger will fire post change trigger will not fire. At the time of execute-query post-chage trigger will fire, on-validate field trigger will not fire.

19. What is the difference between an ON-VALIDATE-FIELD trigger and a trigger ?
On-validate-field trigger fires, when the field Validation status New or changed.
Post-field-trigger whenever the control leaving form the field, it will fire.

20. What is the difference between a POST-FIELD trigger and a POST-CHANGE trigger ?

Post-field trigger fires whenever the control leaving from the filed.
Post-change trigger fires at the time of execute-query procedure invoked or filed validation status changed.

21. When is PRE-QUERY trigger executed ?
When Execute-query or count-query Package procedures are invoked.

22. Give the sequence in which triggers fired during insert operations, when the following 3 triggers are defined at the smae block level ?
a. ON-INSERT b. POST-INSERT c. PRE-INSERT

PRE-INSERT,ON-INSERT & POST-INSERT.

23. Can we use GO-BLOCK package in a pre-field trigger ?
No.

24. Is a Keystartup trigger fires as result of a operator pressing a key explicitly ?
No.

25. How can you execute the user defined triggers in forms 3.0 ?
Execute_Trigger (trigger-name)

26. When does an on-lock trigger fire ?
It will fires whenever SQL * Forms would normally attempt to lock a row.

26. What is Post-Block is a
. a. Navigational Trigger.
b. Key trigger
c. Transaction Trigger.

Navigational Trigger.

27. What is the difference between keystartup and pre-form ?
Key-startup trigger fires after successful navigation into a form.
Pre-form trigger fires before enter into the form.

28. What is the difference between keystartup and pre-form ?
Key-startup triigger fires after successful navigation into a form.
Pre-form trigger fires before enter into the form.

PACKAGE PROCEDURE & FUNCTION

29. What is a Package Procedure ?
A Package proecdure is built in PL/SQL procedure.

30. What are the different types of Package Procedure ?
1. Restricted package procedure.
2. Unrestricted package proecdure.

31. What is the difference between restricted and unrestricted package procedure ?
Restricted package procedure that affects the basic basic functions of SQL * Forms. It cannot used in all triggers execpt key triggers.

Unrestricted package procedure that does not interfere with the basic functions of SQL * Forms it can be used in any triggers.

32. Classify the restricted and unrestricted procedure from the following.
a. Call
b. User-Exit
c. Call-Query
d. Up
e. Execute-Query
f. Message
g. Exit-From
h. Post
i. Break

a. Call - unrestricted
b. User Exit - Unrestricted
c. Call_query - Unrestricted
d. Up - Restricted
e. Execute Query - Restricted
f. Message - Restricted
g. Exit_form - Restricted
h. Post - Restricted
i. Break - Unrestricted.

33. Can we use a restricted package procedure in ON-VALIDATE-FIELD Trigger ?
No.

34. What SYNCHRONIZE procedure does ?
It synchoronizes the terminal screen with the internal state of the form.

35. What are the unrestricted procedures used to change the popup screen position during run time ?
Anchor-view
Resize -View
Move-View.

36. What Enter package procedure does ?
Enter Validate-data in the current validation unit.

37. What ERASE package procedure does ?
Erase removes an indicated global variable.

38. What is the difference between NAME_IN and COPY ?
Copy is package procedure and writes values into a field.
Name in is a package function and returns the contents of the variable to which you apply.

38. Identify package function from the following ?
1. Error-Code
2. Break
3. Call
4. Error-text
5. Form-failure
6. Form-fatal
7. Execute-query
8. Anchor_View
9. Message_code


1. Error_Code
2. Error_Text
3. Form_Failure
4. Form_Fatal
5. Message_Code

40. How does the command POST differs from COMMIT ?

Post writes data in the form to the database but does not perform database commit
Commit permenently writes data in the form to the database.

41. What the PAUSE package procedure does ?
Pause suspends processing until the operator presses a function key

42. What package procedure is used for calling another form ?
Call (E.g. Call(formname)

43. What package procedure used for invoke sql *plus from sql *forms ?
Host (E.g. Host (sqlplus))

44. Error_Code is a package proecdure ?
a. True b. false
False.

45. EXIT_FORM is a restricted package procedure ?
a. True b. False
True.

46. When the form is running in DEBUG mode, If you want to examine the values of global variables and other form variables, What package procedure command you would use in your trigger text ?