About Triggers:
1.
What is triggers?
What are the different types of triggers?
A
database trigger is a stored subprogram associated with a database table, view,
or event. For instance, you can have Oracle fire a trigger automatically before
or after
an
INSERT,
UPDATE,
or DELETE statement
affects a table.
A Database Trigger is a stored procedure that is fired
when a DML operation is performed on the table. In total there are 13 types of
Triggers
Syntax for
creating a trigger:
CREATE OR REPLACE TRIGGER <TRIGGERNAME>
before / after
[INSERT / UPDATE / DELETE ] ON
<TABLE NAME>
{For each Statement / Row}
{When <condition…..>}
Types of
Triggers:
Before
After
For each
Row
For each
Statement (default)
Instead of Trigger: This trigger is defined on a view
rather than a table.
System Triggers: A new feature of Oracle8i, wherein
the trigger is fired when the database startup / shutdown process.
Schema Triggers: These triggers are fired whenever a
DDL statement is executed. (Creation or
Deletion of any DB Objects)
Order of Trigger Firing:
·
Before Statement trigger (If present)
·
Each row affected by the statement
(a) Execute row
level trigger (If present)
(b) Execute the
statement itself
(c) Execute the
after row level trigger (If Present)
·
After statement trigger (If Present)
2.
What are the different types of joins available in Oracle?
Equi Join: When primary and foreign key relationship exists between
the tables that are going to be joined.
Self Join: If comparison comes in a single table
Cartesian Join: When tables are joined without
giving any join condition.
Inner Join: The resultant set includes all the
rows that satisfy the join condition.
Outer Join: The resultant set includes the rows
which doesn’t satisfy the join condition.
The outer join operator Plus sign (+) will be included in the join condition.
Example: SELECT a. column1, a. column2, b.column3….. From a, b
where
a.column1 (+)
=b.Column1
Here the
rows from table which doesn’t satisfy the join condition will also be fetched.
3.
What are Indexes?
What are the different types of Index? If a table consists of more than
one Index how to enforce the statement to use the second Index?
An Index is
a DB object, which is used to improve the performance of the data retrieval.
CREATE
INDEX <INDEX NAME> ON <TABLE name>.(<COLUMN name>)
Types of
Indexes:
Bitmap
Index (Used for Low cardinality column)
Btree Index
(Used for high cardinality column)
Note: It is
not possible to crea
4.
What is Mutating Table?
Table under
transition is called Mutating Table.
5.
What is views? What
is Inline View??
Views are
window to a table. It contains no data,
it is based on the actual table called the base table or a view.
Inline View
means writing select statement in the Query itself instead of selecting a
Column Name.
6. What is a Cursor? When it is used? What are different types of Cursors.
Cursor is a private SQL area created in SGA to do
multi row operation in a PL/SQL programme
Explicit Cursor,
Implicit Cursor.
Implicit Cursor: System (Oracle) automatically
declares and uses for all DML SQL Statements.
Explicit Cursor: Cursor declared explicitly in the
PL/SQL programme to do multi row operation
Syntax:
Declare
Cursor C1 is SELECT SAL, EMPNO FROM EMP
X number;
Y Varchar2(30);
Begin
Open C1;
Loop
Fetch C1
INTO x, y;
Exit when c1%NOTFOUND
End Loop;
End;
7. What is for Cursor? When it is used? Is it necessary to write an explicit exit in
case for Cursor?
A Cursor for loop can be
used simplify the explicit cursor, no need to explicitly Open, fetch and
close. No explicity EXIT statement is
required.
8. What are Cursor attributes?
What is use of FOR UPDATE in Cursor?
%Found
%NotFound
%RowCount
%IsOpen
FOR
UPDATE statement in Cursor is used to update a Column in the selected table by
using the CURRENT OF <cursor name>.
9. What is a Package? What is the advantage of using Packages?
A Package is a PL/SQL Construct that allow related
object to be stored together. Package
contains 2 parts, Package Specification and Package Body, each stored
separately in the Data Dicitionary.
Once the Package is called all the related Procedure
and functions of the package gets compiled and stored in the memory as P-code.
How do u call a Package.
<PackageName>.<Procedure / Function
Name> (Related Parameters….)
10. Name some important Packages
provided by Oracle?
DBMS_SQL, DBMS_JOBS, DBMS_DDL, DBMS_LOCK
11. What is Overloading?
Overloading is oops concept(Object Oriented
Programming)
By Using the same name we can write any number of
Procedure or functions in a package but either number of parameters in the
procedure/function must be vary or parameter datatype must vary.
12. What is a Function? Difference between Procedure and Function?
Function is a object that takes one or more
arguments and returns only value. But in case of procedures we can return more
than one parameters.
Function always returns a value, whereas procedure
may or may not return a value.
13. What is the Package used in
Oracle to do the File Operation?
UTL_FILE
14. What is Dynamic SQL? How Dynamic SQL can be built?
The SQL statement which are built at run time are
called the Dynamic SQL. Dynamic SQL can
be built by using DBMS_SQL package.
Procedure of Dynamic SQL
OPEN_CURSOR, PARSE, BIND_VARIABLE, DEFINE_COLUMN,
EXECUTE, FETCH_ROWS, CLOSE_CURSOR.
Oracle8i onwards there is another built in to
construct Dynamic SQL called EXECUTE_IMMEDIATE.
15. What is an exception? What are the different types of
Exception? How do u
declare a user defined
exception?
The error condition in
PL/SQL is termed as an exception. Two types of
Exception:
Pre-Defined Exception: Example No_Data_Found, Storage_Error,
Zero_Error, Invlid_Cursor,
Too_Many_Rows
User-Defined Exception: Anything
Syntax:
Declare
Xyz Exception;
Begin
SELECT ENAME FROM EMP
RAISE XYZ;
End;
16. what could happen if we use
WHEN OTHERS before any predefined exceptions
According to the Oracle standards “ When Others “
exception must be the last exception. All the Predefined exceptions must be
used before the “When others” exception.
If
“ When others” exception used before any pre-defined exceptions then procedure/function shows the compilations
errors
17. List out some features in 8i
Bitmap Indexes, Drop a Column, Bulk Insert and Bulk
Update
Materialized views, Dynamic Sql(Execute Immediate
etc)
18. List some 9iFeatures
External tables ( We query the data directly from a
file like select * from “c:/abcd.csv” )
Multi Table Insert with single command, resumable
process etc.
19. What are SQLCODE and SQLERRM
and why are they important for PL/SQL
developers?
SQLCODE returns the value of the error number for
the last error encountered. The SQLERRM returns the actual error message for
the last error encountered. They can be used in exception handling to report,
or, store in an error log table, the error that occurred in the code. These are
especially useful for the WHEN OTHERS exception
20. What is the use of
Pragma_Init exception
By using this we can define our messages by handling
the oracle messages
21. What are temporary tables?
How many types?
Temporary tables are used to store the data
temporarly. Mainly there are 2 types
They are transaction and Session types
Syntax: Create global temporary table
<temp_tab> as select * from emp;
This temporarly table is used to store the data
temparorly once you exit from session then that table will get erased
22. Some of the System Tables
a. User_source table will
stores the information of the user defined definitions
b. All_Source and dba_source
tables will stores the system defined schema objects definitions as well as
user defined.
c. All_Tab_Columns and
ben_all_tab_columns are used to list out
the all the columns name and respected table names also.
23. Write a query to list out
the employees with their respective manager levels?
select lpad('*', level * 2), empno, ename, mgr from
emp
connect by prior empno = mgr start with empno = 7839
It results the hierarchy of the employees
Note : For Answers Check the Next Page
* What is PL/SQL and what is it used
for?
* Should one use PL/SQL or Java to code procedures
and triggers?
* How can one see if somebody modified
any code?
* How can one search PL/SQL code for a
key?
* How can one keep a history of PL/SQL
code changes?
* How can I protect my PL/SQL source
code?
* Can one print to the screen from PL/SQL?
* Can one read/write files from PL/SQL?
* Can one call DDL statements from
PL/SQL?
* Can one use dynamic SQL statements
from PL/SQL?
* What is the difference between %TYPE
and %ROWTYPE?
* How does one get the value of a
sequence into a PL/SQL variable?
* Can one execute an operating system
command from PL/SQL?
* How does one loop through tables in
PL/SQL?
* How often should one COMMIT in a
PL/SQL loop? / What is the best commit strategy?
* I can SELECT from SQL*Plus but not
from PL/SQL. What is wrong?
* What is a mutating and constraining
table?
* Can one pass an object/table as an
argument to a remote procedure?
* Is it better to put code in triggers
or procedures? What is the difference?
* Is there a PL/SQL Engine in SQL*Plus?
* Is there a limit on the size of a
PL/SQL block?
* Where can one find more info about
PL/SQL?
What is PL/SQL and what is it used for?
PL/SQL is Oracle's Procedural Language
extension to SQL. PL/SQL's language syntax, structure and data types are
similar to that of ADA.
The PL/SQL language includes object oriented programming techniques such as
encapsulation, function overloading, information hiding (all but inheritance).
PL/SQL is commonly used to write data-centric programs to manipulate data in an
Oracle database.
Should one use PL/SQL or Java to code
procedures and triggers?
Internally the Oracle database supports
two procedural languages, namely PL/SQL and Java. This leads to questions like
"Which of the two is the best?" and "Will Oracle ever desupport
PL/SQL in favour of Java?".
Many Oracle applications are based on
PL/SQL and it would be difficult of Oracle to ever desupport PL/SQL. In fact,
all indications are that PL/SQL still has a bright future ahead of it. Many
enhancements are still being made to PL/SQL. For example, Oracle 9iDB supports
native compilation of Pl/SQL code to binaries.
PL/SQL and Java appeal to different
people in different job roles. The following table briefly describes the
difference between these two language environments:
PL/SQL:
Data centric and tightly integrated into
the database
Proprietary to Oracle and difficult to
port to other database systems
Data manupilation is slightly faster in
PL/SQL than in Java
Easier to use than Java (depending on
your background)
Java:
Open standard, not proprietary to Oracle
Incurs some data conversion overhead
between the Database and Java type systems
Java is more difficult to use (depending
on your background)
How can one see if somebody modified any
code?
Code for stored procedures, functions
and packages is stored in the Oracle Data Dictionary. One can detect code
changes by looking at the LAST_DDL_TIME column in the USER_OBJECTS dictionary
view. Example:
SELECT OBJECT_NAME,
TO_CHAR(CREATED, 'DD-Mon-RR HH24:MI') CREATE_TIME,
TO_CHAR(LAST_DDL_TIME,
'DD-Mon-RR HH24:MI') MOD_TIME,
STATUS
FROM USER_OBJECTS
WHERE LAST_DDL_TIME >
'&CHECK_FROM_DATE';
How can one search PL/SQL code for a
key?
The following query is handy if you want
to know where a certain table, field or expression is referenced in your PL/SQL
source code.
SELECT TYPE, NAME, LINE
FROM USER_SOURCE
WHERE UPPER(TEXT) LIKE
'%&KEYWORD%';
* By useing DBA_DEPENDENCIES table you
can find out. - Ezhil
How can one keep a history of PL/SQL
code changes?
One can build a history of PL/SQL code
changes by setting up an AFTER CREATE schema (or database) level trigger
(available from Oracle 8.1.7). This way one can easily revert to previous code
should someone make any catastrophic changes. Look at this example:
CREATE TABLE SOURCE_HIST -- Create history table
AS SELECT SYSDATE CHANGE_DATE, USER_SOURCE.*
FROM USER_SOURCE WHERE 1=2;
CREATE OR REPLACE TRIGGER change_hist -- Store code in hist table
AFTER CREATE ON
SCOTT.SCHEMA -- Change SCOTT to
your schema name
DECLARE
BEGIN
if DICTIONARY_OBJ_TYPE in ('PROCEDURE', 'FUNCTION',
'PACKAGE', 'PACKAGE
BODY', 'TYPE') then
-- Store old code in SOURCE_HIST
table
INSERT INTO SOURCE_HIST
SELECT sysdate, user_source.*
FROM USER_SOURCE
WHERE TYPE =
DICTIONARY_OBJ_TYPE
AND NAME =
DICTIONARY_OBJ_NAME;
end if;
EXCEPTION
WHEN OTHERS THEN
raise_application_error (-20000,
SQLERRM);
END;
/
show errors
How can I protect my PL/SQL source code?
PL/SQL V2.2, available with Oracle7.2,
implements a binary wrapper for PL/SQL programs to protect the source code.
This is done via a standalone utility
that transforms the PL/SQL source code into portable binary object code
(somewhat larger than the original). This way you can distribute software
without having to worry about exposing your
proprietary algorithms and methods.
SQL*Plus and SQL*DBA will still understand and know how to execute such
scripts. Just be careful, there is no "decode" command available.
The syntax is:
wrap
iname=myscript.sql oname=xxxx.plb
Can one print to the screen from PL/SQL?
One can use the DBMS_OUTPUT package to
write information to an output buffer. This buffer can be displayed on the screen
from SQL*Plus if you issue the SET SERVEROUTPUT
ON; command. For example:
set
serveroutput on
begin
dbms_output.put_line('Look Ma, I can print
from PL/SQL!!!');
end;
/
DBMS_OUTPUT is useful for debugging
PL/SQL programs. However, if you print too much, the output buffer will
overflow. In that case, set the buffer size to a larger value, eg.: set
serveroutput on size 200000
If you forget to set serveroutput on
type SET SERVEROUTPUT ON once you remember, and then EXEC NULL;. If you haven't
cleared the DBMS_OUTPUT buffer with the disable or enable procedure, SQL*Plus
will display the entire contents of the buffer when it executes this dummy
PL/SQL block.
Can one read/write files from PL/SQL?
Included in Oracle 7.3 is an UTL_FILE
package that can read and write operating system files. The directory you
intend writing to has to be in your INIT.ORA file (see UTL_FILE_DIR=...
parameter). Before Oracle 7.3 the only means of writing a file was to use
DBMS_OUTPUT with the SQL*Plus SPOOL command.
Copy this example to get started:
DECLARE
fileHandler UTL_FILE.FILE_TYPE;
BEGIN
fileHandler := UTL_FILE.FOPEN('/tmp',
'myfile', 'w');
UTL_FILE.PUTF(fileHandler, 'Look ma, I''m
writing to a file!!!\n');
UTL_FILE.FCLOSE(fileHandler);
EXCEPTION
WHEN utl_file.invalid_path THEN
raise_application_error(-20000, 'ERROR:
Invalid path for file or path not in INIT.ORA.');
END;
/
Can one call DDL statements from PL/SQL?
One can call DDL statements like CREATE,
DROP, TRUNCATE, etc. from PL/SQL by using the "EXECUTE IMMEDATE"
statement. Users running Oracle versions below 8i can look at the DBMS_SQL
package (see FAQ about Dynamic SQL).
begin
EXECUTE IMMEDIATE 'CREATE TABLE X(A DATE)';
end;
NOTE: The DDL statement in quotes should
not be terminated with a semicolon.
Can one use dynamic SQL statements from
PL/SQL?
From PL/SQL V2.1 one can use the
DBMS_SQL package to execute dynamic SQL statements. Eg:
CREATE
OR REPLACE PROCEDURE DYNSQL AS
cur integer;
rc integer;
BEGIN
cur := DBMS_SQL.OPEN_CURSOR;
DBMS_SQL.PARSE(cur, 'CREATE TABLE X (Y
DATE)', DBMS_SQL.NATIVE);
rc := DBMS_SQL.EXECUTE(cur);
DBMS_SQL.CLOSE_CURSOR(cur);
END;
/
Another example:
CREATE
OR REPLACE PROCEDURE DEPARTMENTS(NO IN DEPT.DEPTNO%TYPE) AS
v_cursor integer;
v_dname char(20);
v_rows integer;
BEGIN
v_cursor := DBMS_SQL.OPEN_CURSOR;
DBMS_SQL.PARSE(v_cursor,
'select dname from dept where deptno > :x', DBMS_SQL.V7);
DBMS_SQL.BIND_VARIABLE(v_cursor, ':x', no);
DBMS_SQL.DEFINE_COLUMN_CHAR(v_cursor, 1,
v_dname, 20);
v_rows := DBMS_SQL.EXECUTE(v_cursor);
loop
if DBMS_SQL.FETCH_ROWS(v_cursor) = 0 then
exit;
end if;
DBMS_SQL.COLUMN_VALUE_CHAR(v_cursor, 1,
v_dname);
DBMS_OUTPUT.PUT_LINE('Deptartment name:
'||v_dname);
end loop;
DBMS_SQL.CLOSE_CURSOR(v_cursor);
EXCEPTION
when others then
DBMS_SQL.CLOSE_CURSOR(v_cursor);
raise_application_error(-20000, 'Unknown
Exception Raised: '||sqlcode||' '||sqlerrm);
END;
/
What is the difference between %TYPE and
%ROWTYPE?
The %TYPE and %ROWTYPE constructs
provide data independence, reduces maintenance costs, and allows programs to
adapt as the database changes to meet new business needs.
%ROWTYPE is used to declare a record
with the same types as found in the specified database table, view or cursor.
Example:
DECLARE
v_EmpRecord
emp%ROWTYPE;
%TYPE is used to declare a field with
the same type as that of a specified table's column. Example:
DECLARE
v_EmpNo
emp.empno%TYPE;
How does one get the value of a sequence
into a PL/SQL variable?
As you might know, oracle prohibits
this:
i
:= sq_sequence.NEXTVAL;
(for some silly reason). But you can do
this:
select
sq_sequence.NEXTVAL into :i from dual;
Thanks to Ronald van Woensel
Can one execute an operating system
command from PL/SQL?
There is no direct way to execute
operating system commands from PL/SQL in Oracle7. However, one can write an
external program (using one of the precompiler languages, OCI or Perl with Oracle
access modules) to act as a listener on a database pipe (SYS.DBMS_PIPE). Your
PL/SQL program then put requests to run commands in the pipe, the listener
picks it up and run the requests. Results are passed back on a different
database pipe. For an Pro*C example, see chapter 8 of the Oracle Application
Developers Guide.
In Oracle8 one can call external 3GL
code in a dynamically linked library (DLL or shared object). One just write a
library in C/ C++ to do whatever is required. Defining this C/C++ function to
PL/SQL makes it executable. Look at this External Procedure example.
How does one loop through tables in
PL/SQL?
Look at the following nested loop code
example.
DECLARE
CURSOR dept_cur IS
SELECT deptno
FROM dept
ORDER BY deptno;
-- Employee cursor all employees for a dept
number
CURSOR emp_cur (v_dept_no DEPT.DEPTNO%TYPE)
IS
SELECT ename
FROM emp
WHERE deptno = v_dept_no;
BEGIN
FOR dept_rec IN dept_cur LOOP
dbms_output.put_line('Employees in Department
'||TO_CHAR(dept_rec.deptno));
FOR emp_rec in emp_cur(dept_rec.deptno)
LOOP
dbms_output.put_line('...Employee is
'||emp_rec.ename);
END LOOP;
END LOOP;
END;
/
How often should one COMMIT in a PL/SQL
loop? / What is the best commit strategy?
Contrary to popular believe, one should
COMMIT less frequently within a PL/SQL loop to prevent ORA-1555 (Snapshot too
old) errors. The higher the frequency of commit, the sooner the extents in the
rollback segments will be cleared for new transactions, causing ORA-1555
errors.
To fix this problem one can easily
rewrite code like this:
FOR
records IN my_cursor LOOP
...do some stuff...
COMMIT;
END
LOOP;
... to ...
FOR
records IN my_cursor LOOP
...do some stuff...
i := i+1;
IF mod(i, 10000) THEN -- Commit every 10000 records
COMMIT;
END IF;
END
LOOP;
If you still get ORA-1555 errors,
contact your DBA to increase the rollback segments.
NOTE: Although fetching across COMMITs
work with Oracle, is not supported by the ANSI standard.
I can SELECT from SQL*Plus but not from
PL/SQL. What is wrong?
PL/SQL respect object privileges given
directly to the user, but does not observe privileges given through roles. The
consequence is that a SQL statement can work in SQL*Plus, but will give an
error in PL/SQL. Choose one of the following solutions:
Grant direct access on the tables to
your user. Do not use roles!
GRANT
select ON scott.emp TO my_user;
Define your procedures with invoker
rights (Oracle 8i and higher);
Move all the tables to one user/schema.
What is a mutating and constraining
table?
"Mutating" means
"changing". A mutating table is a table that is currently being
modified by an update, delete, or insert statement. When a trigger tries to
reference a table that is in state of flux (being changed), it is considered
"mutating" and raises an error since Oracle should not return data
that has not yet reached its final state.
Another way this error can occur is if
the trigger has statements to change the primary, foreign or unique key columns
of the table off which it fires. If you must have triggers on tables that have
referential constraints, the workaround is to enforce the referential integrity
through triggers as well.
There are several restrictions in Oracle
regarding triggers:
A row-level trigger cannot query or
modify a mutating table. (Of course, NEW and OLD still can be accessed by the
trigger) .
A statement-level trigger cannot query
or modify a mutating table if the trigger is fired as the result of a CASCADE
delete.
Etc.
Can one pass an object/table as an
argument to a remote procedure?
The only way the same object type can be
referenced between two databases is via a database link. Note that it is not
enough to just use the same type definitions. Look at this example:
--
Database A: receives a PL/SQL table from database B
CREATE
OR REPLACE PROCEDURE pcalled(TabX DBMS_SQL.VARCHAR2S) IS
BEGIN
-- do something with TabX from database B
null;
END;
/
--
Database B: sends a PL/SQL table to database A
CREATE
OR REPLACE PROCEDURE pcalling IS
TabX DBMS_SQL.VARCHAR2S@DBLINK2;
BEGIN
pcalled@DBLINK2(TabX);
END;
/
Is it better to put code in triggers or
procedures? What is the difference?
In earlier releases of Oracle it was
better to put as much code as possible in procedures rather than triggers. At
that stage procedures executed faster than triggers as triggers had to be
re-compiled every time before executed (unless cached). In more recent releases
both triggers and procedures are compiled when created (stored p-code) and one
can add as much code as one likes in either procedures or triggers.
Is there a PL/SQL Engine in SQL*Plus?
No. Unlike Oracle Forms, SQL*Plus does
not have a PL/SQL engine. Thus, all your PL/SQL is sent directly to the
database engine for execution. This makes it much more efficient as SQL
statements are not stripped off and sent to the database individually.
Is there a limit on the size of a PL/SQL
block?
Yes, the max size is not an explicit
byte limit, but related to the parse tree that is created when you compile the
code. You can run the following select statement to query the size of an
existing package or procedure:
SQL>
select * from dba_object_size where name = 'procedure_name';
Forms/Reports
1.
How you declare global variables in forms ?
Global variable will declared in
When-New-Form-Instance Triggers
2.
What are Table Handlers and Event Handlers?
3.
What are new feature in forms 6i compared to forms4.5
4.What
is the Difference between callform, Newform, Openform
5.What
is the Use of Program Units in form/reports ?
6.How
many triggers is there in reports and what are they and what is the Order of
firing
Before Parameter Form
After Parameter Form
Before report
Between pages
After Report
7.Which
trigger will get fired while opening an LOV in forms
Key-List-Value
8.
How Many Types of reports are there? Name it??
9. What
is the Use of Anchors in Reports
10.
What is the uses and differences between Summary Column, Formula column and
Place holder column?
11.
What is the Difference between Bind parameter
and lexical parameter? Which trigger will be used to specify the
conditions for a lexical parameter.
12.
What is the use of Destype, Desname, Desformat in Parameter form.
13.When
the Between Pages Trigger will fire?
After first page this trigger will fire
until last
page and after that for last page it wont
fire.
14.
What are the form Modules?
They are 4 types of form modules are
there 1) Alerts 2) Forms Modules 3) Menu
Modules 4) PLSQL Libraries
15.Some
of the New Features in Reports6i
In 6i we can generate the report in
different types like PDF,HTML,XML, RTF etc
In reports goto -> Layout model à Header or Body or Margin
sections à property
Pallateà Distributions. Specify the Type and file name with path.
Then gotoà File à Distribute.
16.
What is the difference between Format Triggers and Action Triggers
Action Trigger is Procedure whereas Format Trigger is Procedure
By using Action trigger we can open the
other form or report
17
What is the Difference between FlexMode and Confine Mode and their differences
18.
What is the Order of triggers firing
W-N-F-I, Pre-Form, W-N-I-I, W-N-B-I ??
19
What is the Major Differences and uses between Property Class and Visual
Attribute
20.
Other than Run_Product how can we run a report from a form
By using
Run_Report_Object function we can run the reports( This is 6i New
Feature)
To use this Add that report in Form Object
Navigator and pass the Id of that report.
21.
What are the Default triggers will be created when a master-detail form is
created
There are 3 types are triggers will be created
in form level when a master-detail form is
created.
22.
What is the Diiference between .pll, .pls and .plx in Libraries
23.
What is Object Library and Attached Library
Object Library can be used to stored
Function, Procedure, Package. Attached library will be used to avoid any change
in source code. Object library can be converted into .PLX and attached to
Attache library.
24 What is the difference between writing code
in Programme Unit and Library Files?
The code written in Programme unit is
form’s specific, whereas code written in
Library files, can be used across the
forms.
25. When a form is run, which
are the triggers fire, and in what sequence they fire?
PRE-FORM
WHEN-NEW-FORM-INSTANCE
PRE-BLOCK
WHEN-NEW-BLOCK-INSTANCE
WHEN-NEW-ITEM-INSTANCE
POST-BLOCK
POST-FORM
1. What is the difference
between Forms 4.5 and Forms 6i
Tab Page utility is not available in 4.5 Version
2. What is the utility used to
call the report from the forms?
RUN_REPORT
3. What is a Property Class?
Different methods of creating property class?
Property Class is defining properties of objects
along with their settings. The property
class inheritance allows the user to perform global changes very quickly and
efficiently.
Methods:
Object Navigator Method
Properties Window Method
4. WHEN-NEW-FORM trigger
written at Form Level, Block Level and Item Level
which one will fire first?
The trigger
written at the lower level Item Level Fires first then at Block Level and at
last it fires in Form Level.
5. In the previous question circumstance,
is it possible to change the order of trigger
Execution? If
Yes, where it needs to be changed?
Yes, in the trigger property (Before, After,
Default)by changing the attributes.
6. What are the different kinds
of Parameters available in the report?
System and User defined Parameters.(Bind and Lexical Parameters)
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