Oracle Interview Questions – Part 12
Q.What are OPEN_FORM,CALL_FORM,NEW_FORM? diff?
CALL_FORM : It calls the other form. but parent remains active, when called form completes the operation , it releases lock and control goes back to the calling form.
When you call a form, Oracle Forms issues a savepoint for the called form. If the CLEAR_FORM function causes a rollback when the called form is current, Oracle Forms rolls back uncommitted changes to this savepoint.
OPEN_FORM : When you call a form, Oracle Forms issues a savepoint for the called form. If the CLEAR_FORM function causes a rollback when the called form is current, Oracle Forms rolls back uncommitted changes to this savepoint.
NEW_FORM : Exits the current form and enters the indicated form. The calling form is terminated as the parent form. If the calling form had been called by a higher form, Oracle Forms keeps the higher call active and treats it as a call to the new form. Oracle Forms releases memory (such as database cursors) that the terminated form was using.
Oracle Forms runs the new form with the same Runform options as the parent form. If the parent form was a called form, Oracle Forms runs the new form with the same options as the parent form.
Q.What is call form stack?
When successive forms are loaded via the CALL_FORM procedure, the resulting module hierarchy is known as the call form stack.
Q.What is a visual attribute?
Visual attributes are the font, color, and pattern properties that you set for form and menu objects that appear in your application’s interface.
Q.Difference between VAT and Property Class?
Named visual attributes define only font, color, and pattern attributes; property classes can contain these and any other properties.
You can change the appearance of objects at runtime by changing the named visual attribute programmatically; property class assignment cannot be changed programmatically. When an object is inheriting from both a property class and a named visual attribute, the named visual attribute settings take precedence, and any visual attribute properties in the class are ignored.
Q.Which trigger related to mouse?
Q.Can u port applications across the platforms? how?
Yes we can port applications across platforms.Consider the form developed in a windows system.The form would be generated in unix system by using f45gen my_form.fmb scott/tiger
Q.What is Current record attribute property?
Specifies the named visual attribute used when an item is part of the current record. Current Record Attribute is frequently used at the block level to display the current row in a multi-record If you define an item-level Current Record Attribute, you can display a pre-determined item in a special color when it is part of the current record, but you cannot dynamically highlight the current item, as the input focus changes.
Q.Can u set default font in forms?
Yes. Change windows registry(regedit). Set form45_font to the desired font._break
Q.What is Log Switch?
The point at which ORACLE ends writing to one online redo log file and begins writing to another is called a log switch.
Q.What is Archived Redo Log?
Archived Redo Log consists of Redo Log files that have archived before being reused.
Q.What is On-line Redo Log?
The On-line Redo Log is a set of tow or more on-line redo files that record all committed changes made to the database. Whenever a transaction is committed, the corresponding redo entries temporarily stores in redo log buffers of the SGA are written to an on-line redo log file by the background process LGWR. The on-line redo log files are used in cyclical fashion.
Q.Can u change VAT at run time?
Yes. You can programmatically change an object’s named visual attribute setting to change the font, color, and pattern of the object at runtime.
Q.Which parameter specified in the DEFAULT STORAGE clause of CREATE TABLESPACE cannot be altered after creating the tablespace?
All the default storage parameters defined for the tablespace can be changed using the ALTER TABLESPACE command. When objects are created their INITIAL and MINEXTENS values cannot be changed.
Q.What are the steps involved in Database Startup?
Start an instance, Mount the Database and Open the Database.
Rolling forward to recover data that has not been recorded in data files, yet has been recorded in the on-line redo log, including the contents of rollback segments. Rolling back transactions that have been explicitly rolled back or have not been committed as indicated by the rollback segments regenerated in step a. Releasing any resources (locks) held by transactions in process at the time of the failure. Resolving any pending distributed transactions undergoing a two-phase commit at the time of the instance failure.
Q.Can Full Backup be performed when the database is open?
Q.What are the advantages of operating a database in ARCHIVELOG mode over operating it in NO ARCHIVELOG mode?
Complete database recovery from disk failure is possible only in ARCHIVELOG mode. Online database backup is possible only in ARCHIVELOG mode.
Q.What is OLE Activation style property?
Specifies the event that will activate the OLE containing item.
Q.What are the steps involved in Database Shutdown?
Close the Database, Dismount the Database and Shutdown the Instance.
Q.What are the different modes of mounting a Database with the Parallel Server?
Exclusive Mode If the first instance that mounts a database does so in exclusive mode, only that Instance can mount the database.
Parallel Mode If the first instance that mounts a database is started in parallel mode, other instances that are started in parallel mode can also mount the database.
Q.What is Restricted Mode of Instance Startup?
An instance can be started in (or later altered to be in) restricted mode so that when the database is open connections are limited only to those whose user accounts have been granted the RESTRICTED SESSION system privilege.
Q.Can u have OLE objects in forms?
Q.Can u have VBX and OCX controls in forms?
Q.What r the types of windows (Window style)?
Specifies whether the window is a Document window or a Dialog window.
Q.Can u change the mouse pointer ? How?
Yes. Specifies the mouse cursor style. Use this property to dynamically change the shape of the cursor.
Q.Can u have more than one layout in a report?
It is possible to have more than one layout in a report by using the additional layout option in the layout editor.
Q.Can u run the report with out a parameter form?
Yes it is possible to run the report without parameter form by setting the PARAM value to Null
Q.What is Flex?
Flex is the property of moving the related fields together by setting the flex property on
Q.What is the lock option in reports layout?
By using the lock option we cannot move the fields in the layout editor outside the frame. This is useful for maintaining the fields .
Q.What is a Private Synonyms?
A Private Synonyms can be accessed only by the owner.
Q.What is a Synonym?
A synonym is an alias for a table, view, sequence or program unit.
Q.What is schema?
A schema is collection of database objects of a User.
Q.What is index cluster?
A cluster with an index on the cluster key.
Q.What is a Sequence?
A sequence generates a serial list of unique numbers for numerical columns of a database’s tables.
Q.Describe Referential Integrity?
A rule defined on a column (or set of columns) in one table that allows the insert or update of a row only if the value for the column or set of columns (the dependent value) matches a value in a column of a related table (the referenced value). It also specifies the type of data manipulation allowed on referenced data and the action to be performed on dependent data as a result of any action on referenced data.
Q.What is a Segment?
A segment is a set of extents allocated for a certain logical structure.
Q.What is Database Link?
A database link is a named object that describes a “path” from one database to another.
Q.How many types of columns are there and what are they?
Formula columns :: For doing mathematical calculations and returning one value Summary Columns :: For doing summary calculations such as summations etc. Place holder Columns :: These columns are useful for storing the value in a variable
Q.What is hash cluster?
A row is stored in a hash cluster based on the result of applying a hash function to the row’s cluster key value. All rows with the same hash key value are stores together on disk.
Q.When can hash cluster used?
Hash clusters are better choice when a table is often queried with equality queries. For such queries the specified cluster key value is hashed. The resulting hash key value points directly to the area on disk that stores the specified rows.
Q.What are the minimum number of groups required for a matrix report?
The minimum of groups required for a matrix report are 4 e —–