Set - 7

Question 1 :

Table Space,Data Files,Parameter File, Control Files

Answer :

Table Space :: The table space is useful for storing the data in the database.When a database is created two table spaces are created.
a) System Table space :: This data file stores all the tables related to the system and dba tables
b) User Table space :: This data file stores all the user related tables
We should have seperate table spaces for storing the tables and indexes so that the access is fast.
Data Files :: Every Oracle Data Base has one or more physical data files.They store the data for the database.Every datafile is associated with only one database.Once the Data file is created the size cannot change.To increase the size of the database to store more data we have to add data file.
Parameter Files :: Parameter file is needed to start an instance.A parameter file contains the list of instance configuration parameters e.g.::
db_block_buffers = 500
db_name = ORA7
db_domain = u.s.acme lang
Control Files :: Control files record the physical structure of the data files and redo log files
They contain the Db name, name and location of dbs, data files ,redo log files and time stamp.


Question 2 :

Physical Storage of the Data

Answer :

The finest level of granularity of the data base are the data blocks.
Data Block :: One Data Block correspond to specific number of physical database space
Extent :: Extent is the number of specific number of contigious data blocks.
Segments :: Set of Extents allocated for Extents. There are three types of Segments
a) Data Segment :: Non Clustered Table has data segment data of every table is stored in cluster data segment
b) Index Segment :: Each Index has index segment that stores data
c) Roll Back Segment :: Temporarily store 'undo' information


Question 3 :

What are the Pct Free and Pct Used

Answer :

Pct Free is used to denote the percentage of the free space that is to be left when creating a table. Similarly Pct Used is used to denote the percentage of the used space that is to be used when creating a table
eg.:: Pctfree 20, Pctused 40


Question 4 :

What is Row Chaining

Answer :

The data of a row in a table may not be able to fit the same data block.Data for row is stored in a chain of data blocks .


Question 5 :

What is a 2 Phase Commit

Answer :

Two Phase commit is used in distributed data base systems. This is useful to maintain the integrity of the database so that all the users see the same values. It contains DML statements or Remote Procedural calls that reference a remote object. There are basically 2 phases in a 2 phase commit.
a) Prepare Phase :: Global coordinator asks participants to prepare
b) Commit Phase :: Commit all participants to coordinator to Prepared, Read only or abort Reply


Question 6 :

What is the difference between deleting and truncating of tables

Answer :

Deleting a table will not remove the rows from the table but entry is there in the database dictionary and it can be retrieved But truncating a table deletes it completely and it cannot be retrieved.


Question 7 :

What are mutating tables

Answer :

When a table is in state of transition it is said to be mutating. eg :: If a row has been deleted then the table is said to be mutating and no operations can be done on the table except select.


Question 8 :

What are Codd Rules

Answer :

Codd Rules describe the ideal nature of a RDBMS. No RDBMS satisfies all the 12 codd rules and Oracle Satisfies 11 of the 12 rules and is the only Rdbms to satisfy the maximum number of rules.


Question 9 :

What is Normalisation

Answer :

Normalisation is the process of organising the tables to remove the redundancy.There are mainly 5 Normalisation rules.
a) 1 Normal Form :: A table is said to be in 1st Normal Form when the attributes are atomic
b) 2 Normal Form :: A table is said to be in 2nd Normal Form when all the candidate keys are dependant on the primary key
c) 3rd Normal Form :: A table is said to be third Normal form when it is not dependant transitively


Question 10 :

What is the Difference between a post query and a pre query

Answer :

A post query will fire for every row that is fetched but the pre query will fire only once.


Question 11 :

Deleting the Duplicate rows in the table

Answer :

We can delete the duplicate rows in the table by using the Rowid


Question 12 :

Can U disable database trigger? How?

Answer :

Yes. With respect to table
ALTER TABLE TABLE
[[ DISABLE all_trigger ]]


Question 13 :

What is pseudo columns ? Name them?

Answer :

A pseudocolumn behaves like a table column, but is not actually stored in the table. You can select from pseudocolumns, but you cannot insert, update, or delete their values. This section describes these pseudocolumns:
* CURRVAL
* NEXTVAL
* LEVEL
* ROWID
* ROWNUM


Question 14 :

How many columns can table have?

Answer :

The number of columns in a table can range from 1 to 254.
Is space acquired in blocks or extents ?
In extents .


Question 15 :

What is clustered index?

Answer :

In an indexed cluster, rows are stored together based on their cluster key values . Can not applied for HASH.


Question 16 :

What are the datatypes supported By oracle (INTERNAL)?

Answer :

Varchar2, Number,Char , MLSLABEL.


Question 17 :

What are attributes of cursor?

Answer :

%FOUND , %NOTFOUND , %ISOPEN,%ROWCOUNT


Question 18 :

Can you use select in FROM clause of SQL select ?

Answer :

Yes.


Question 19 :

Which trigger are created when master -detail relay?

Answer :

master delete property
* NON-ISOLATED (default)
a) on check delete master
b) on clear details
c) on populate details
* ISOLATED
a) on clear details
b) on populate details
* CASCADE
a) per-delete
b) on clear details
c) on populate details


Question 20 :

which system variables can be set by users?

Answer :

SYSTEM.MESSAGE_LEVEL
SYSTEM.DATE_THRESHOLD
SYSTEM.EFFECTIVE_DATE
SYSTEM.SUPPRESS_WORKING


Question 21 :

What are object group?

Answer :

An object group is a container for a group of objects. You define an object group when you want to package related objects so you can copy or reference them in another module.


Question 22 :

What are referenced objects?

Answer :

Referencing allows you to create objects that inherit their functionality and appearance from other objects. Referencing an object is similar to copying an object, except that the resulting reference object maintains a link to its source object. A reference object automatically inherits any changes that have been made to the source object when you open or regenerate the module that contains the reference object.


Question 23 :

Can you store objects in library?

Answer :

Referencing allows you to create objects that inherit their functionality and appearance from other objects. Referencing an object is similar to copying an object, except that the resulting reference object maintains a link to its source object. A reference object automatically inherits any changes that have been made to the source object when you open or regenerate the module that contains the reference object.


Question 24 :

Is forms 4.5 object oriented tool ? why?

Answer :

yes , partially. 1) PROPERTY CLASS - inheritance property 2) OVERLOADING : procedures and functions.


Question 25 :

Can you issue DDL in forms?

Answer :

yes, but you have to use FORMS_DDL.
Referencing allows you to create objects that inherit their functionality and appearance from other objects. Referencing an object is similar to copying an object, except that the resulting reference object maintains a link to its source object. A reference object automatically inherits any changes that have been made to the source object when you open or regenerate the module that contains the reference object. Any string expression up to 32K:
- a literal
- an expression or a variable representing the text of a block of dynamically created PL/SQL code
- a DML statement or
- a DDL statement
Restrictions:
The statement you pass to FORMS_DDL may not contain bind variable references in the string, but the values of bind variables can be concatenated into the string before passing the result to FORMS_DDL.


Question 26 :

What is SECURE property?

Answer :

- Hides characters that the operator types into the text item. This setting is typically used for password protection.


Question 27 :

What are the types of triggers and how the sequence of firing in text item

Answer :

Triggers can be classified as Key Triggers, Mouse Triggers ,Navigational Triggers.
Key Triggers :: Key Triggers are fired as a result of Key action.e.g :: Key-next-field, Key-up,Key-Down
Mouse Triggers :: Mouse Triggers are fired as a result of the mouse navigation.e.g. When-mouse-button-presed,when-mouse-doubleclicked,etc
Navigational Triggers :: These Triggers are fired as a result of Navigation. E.g. : Post-Text-item,Pre-text-item.
We also have event triggers like when ?new-form-instance and when-new-block-instance.
We cannot call restricted procedures like go_to(?my_block.first_item?) in the Navigational triggers
But can use them in the Key-next-item.
The Difference between Key-next and Post-Text is an very important question. The key-next is fired as a result of the key action while the post text is fired as a result of the mouse movement. Key next will not fire unless there is a key event. The sequence of firing in a text item are as follows ::
a) pre - text
b) when new item
c) key-next
d) when validate
e) post text


Question 28 :

Can you store pictures in database? How?

Answer :

Yes , in long Raw datatype.


Question 29 :

What are property classes ? Can property classes have trigger?

Answer :

Property class inheritance is a powerful feature that allows you to quickly define objects that conform to your own interface and functionality standards. Property classes also allow you to make global changes to applications quickly. By simply changing the definition of a property class, you can change the definition of all objects that inherit properties from that class.
Yes . All type of triggers .


Question 30 :

If you have property class attached to an item and you have same trigger written for the item . Which will fire first?

Answer :

Item level trigger fires , If item level trigger fires, property level trigger won't fire. Triggers at the lowest level are always given the first preference. The item level trigger fires first and then the block and then the Form level trigger.


Question 31 :

What are record groups ? * Can record groups created at run-time?

Answer :

A record group is an internal Oracle Forms data structure that has a column/row framework similar to a database table. However, unlike database tables, record groups are separate objects that belong to the form module in which they are defined. A record group can have an unlimited number of columns of type CHAR, LONG, NUMBER, or DATE provided that the total number of columns does not exceed 64K. Record group column names cannot exceed 30 characters.
Programmatically, record groups can be used whenever the functionality offered by a two-dimensional array of multiple data types is desirable.
TYPES OF RECORD GROUP:
Query Record Group A query record group is a record group that has an associated SELECT statement. The columns in a query record group derive their default names, data types, and lengths from the database columns referenced in the SELECT statement. The records in a query record group are the rows retrieved by the query associated with that record group.
Non-query Record Group A non-query record group is a group that does not have an associated query, but whose structure and values can be modified programmatically at runtime.
Static Record Group A static record group is not associated with a query; rather, you define its structure and row values at design time, and they remain fixed at runtime.


Question 32 :

What are ALERT?

Answer :

An ALERT is a modal window that displays a message notifying operator of some application condition.
Can a button have icon and label at the same time ?
-NO


Question 33 :

What is mouse navigate property of button?

Answer :

When Mouse Navigate is True (the default), Oracle Forms performs standard navigation to move the focus to the item when the operator activates the item with the mouse.
When Mouse Navigate is set to False, Oracle Forms does not perform navigation (and the resulting validation) to move to the item when an operator activates the item with the mouse.


Question 34 :

What is FORMS_MDI_WINDOW?

Answer :

forms run inside the MDI application window. This property is useful for calling a form from another one.


Question 35 :

What are timers ? when when-timer-expired does not fire?

Answer :

The When-Timer-Expired trigger can not fire during trigger, navigation, or transaction processing.


Question 36 :

Can object group have a block?

Answer :

Yes , object group can have block as well as program units.


Question 37 :

How many types of canvases are there.

Answer :

There are 2 types of canvases called as Content and Stack Canvas. Content canvas is the default and the one that is used mostly for giving the base effect. Its like a plate on which we add items and stacked canvas is used for giving 3 dimensional effect.


Question 38 :

What are user-exits?

Answer :

It invokes 3GL programs.


Question 39 :

Can you pass values to-and-fro from foreign function ? how ?

Answer :

Yes . You obtain a return value from a foreign function by assigning the return value to an Oracle Forms variable or item. Make sure that the Oracle Forms variable or item is the same data type as the return value from the foreign function.
After assigning an Oracle Forms variable or item value to a PL/SQL variable, pass the PL/SQL variable as a parameter value in the PL/SQL interface of the foreign function. The PL/SQL variable that is passed as a parameter must be a valid PL/SQL data type; it must also be the appropriate parameter type as defined in the PL/SQL interface.


Question 40 :

What is IAPXTB structure ?

Answer :

The entries of Pro * C and user exits and the form which simulate the proc or user_exit are stored in IAPXTB table in d/b.


Question 41 :

Can you call WIN-SDK thru user exits?

Answer :

YES.


Question 42 :

Does user exits supports DLL on MSWINDOWS ?

Answer :

YES .


Question 43 :

What is path setting for DLL?

Answer :

Make sure you include the name of the DLL in the FORMS45_USEREXIT variable of the ORACLE.INI file, or rename the DLL to F45XTB.DLL. If you rename the DLL to F45XTB.DLL, replace the existing F45XTB.DLL in the ORAWINBIN directory with the new F45XTB.DLL.


Question 44 :

How is mapping of name of DLL and function done?

Answer :

The dll can be created using the Visual C++ / Visual Basic Tools and then the dll is put in the path that is defined the registry.


Question 45 :

What is precompiler?

Answer :

It is similar to C precompiler directives.


Question 46 :

Can you connect to non - oracle datasource ?

Answer :

Yes .


Question 47 :

What are key-mode and locking mode properties? level ?

Answer :

Key Mode : Specifies how oracle forms uniquely identifies rows in the database.This is property includes for application that will run against NON-ORACLE datasources .
Key setting unique (default.)
dateable
n-updateable.

Locking mode :
Specifies when Oracle Forms should attempt to obtain database locks on rows that correspond to queried records in the form. a) immediate b) delayed


Question 48 :

What are savepoint mode and cursor mode properties ? level?

Answer :

Specifies whether Oracle Forms should issue savepoints during a session. This property is included primarily for applications that will run against non-ORACLE data sources. For applications that will run against ORACLE, use the default setting.
Cursor mode - define cursor state across transaction Open/close.


Question 49 :

What is transactional trigger property?

Answer :

Identifies a block as transactional control block. i.e. non - database block that oracle forms should manage as transactional block.(NON-ORACLE datasource) default - FALSE.


Question 50 :

What is OLE automation ?

Answer :

OLE automation allows an OLE server application to expose a set of commands and functions that can be invoked from an OLE container application. OLE automation provides a way for an OLE container application to use the features of an OLE server application to manipulate an OLE object from the OLE container environment. (FORMS_OLE)


Question 51 :

What does invoke built-in do?

Answer :

This procedure invokes a method.
Syntax:
PROCEDURE OLE2.INVOKE
(object obj_type,
method VARCHAR2,
list list_type := 0);
Parameters:
object Is an OLE2 Automation Object.
method Is a method (procedure) of the OLE2 object.
list Is the name of an argument list assigned to the OLE2.CREATE_ARGLIST function.


Question 52 :

What are OPEN_FORM,CALL_FORM,NEW_FORM? diff?

Answer :

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.


Question 53 :

What is call form stack?

Answer :

When successive forms are loaded via the CALL_FORM procedure, the resulting module hierarchy is known as the call form stack.


Question 54 :

Can u port applictions across the platforms? how?

Answer :

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


Question 55 :

What is a visual attribute?

Answer :

Visual attributes are the font, color, and pattern properties that you set for form and menu objects that appear in your application's interface.


Question 56 :

Diff. between VAT and Property Class?

Answer :

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.


Question 57 :

Which trigger related to mouse?

Answer :

When-Mouse-Click
When-Mouse-DoubleClick
When-Mouse-Down
When-Mouse-Enter
When-Mouse-Leave
When-Mouse-Move
When-Mouse-Up


Question 58 :

What is Current record attribute property?

Answer :

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.


Question 59 :

Can u change VAT at run time?

Answer :

Yes. You can programmatically change an object's named visual attribute setting to change the font, color, and pattern of the object at runtime.


Question 60 :

Can u set default font in forms?

Answer :

Yes. Change windows registry(regedit). Set form45_font to the desired font.
_break


Question 61 :

What is Log Switch ?

Answer :

The point at which ORACLE ends writing to one online redo log file and begins writing to another is called a log switch.


Question 62 :

What is On-line Redo Log?

Answer :

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.


Question 63 :

Which parameter specified in the DEFAULT STORAGE clause of CREATE TABLESPACE cannot be altered after creating the tablespace?

Answer :

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.


Question 64 :

What are the steps involved in Database Startup ?

Answer :

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.


Question 65 :

Can Full Backup be performed when the database is open ?

Answer :

No.


Question 66 :

What are the different modes of mounting a Database with the Parallel Server ?

Answer :

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.


Question 67 :

What are the advantages of operating a database in ARCHIVELOG mode over operating it in NO ARCHIVELOG mode ?

Answer :

Complete database recovery from disk failure is possible only in ARCHIVELOG mode. Online database backup is possible only in ARCHIVELOG mode.


Question 68 :

What are the steps involved in Database Shutdown ?

Answer :

Close the Database, Dismount the Database and Shutdown the Instance.


Question 69 :

What is Archived Redo Log ?

Answer :

Archived Redo Log consists of Redo Log files that have archived before being reused.


Question 70 :

What is Restricted Mode of Instance Startup ?

Answer :

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.


Question 71 :

Can u have OLE objects in forms?

Answer :

Yes.


Question 72 :

Can u have VBX and OCX controls in forms ?

Answer :

Yes.


Question 73 :

What r the types of windows (Window style)?

Answer :

Specifies whether the window is a Document window or a Dialog window.


Question 74 :

What is OLE Activation style property?

Answer :

Specifies the event that will activate the OLE containing item.


Question 75 :

Can u change the mouse pointer ? How?

Answer :

Yes. Specifies the mouse cursor style. Use this property to dynamically change the shape of the cursor.


Question 76 :

How many types of columns are there and what are they

Answer :

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
Can u have more than one layout in report
It is possible to have more than one layout in a report by using the additional layout option in the layout editor.


Question 77 :

Can u run the report with out a parameter form

Answer :

Yes it is possible to run the report without parameter form by setting the PARAM value to Null


Question 78 :

What is the lock option in reports layout

Answer :

By using the lock option we cannot move the fields in the layout editor outside the frame. This is useful for maintaining the fields .


Question 79 :

What is Flex

Answer :

Flex is the property of moving the related fields together by setting the flex property on


Question 80 :

What are the minimum number of groups required for a matrix report

Answer :

The minimum of groups required for a matrix report are 4 e -----


Question 81 :

What is a Synonym ?

Answer :

A synonym is an alias for a table, view, sequence or program unit.


Question 82 :

What is a Sequence ?

Answer :

A sequence generates a serial list of unique numbers for numerical columns of a database's tables.


Question 83 :

What is a Segment ?

Answer :

A segment is a set of extents allocated for a certain logical structure.


Question 84 :

What is schema?

Answer :

A schema is collection of database objects of a User.


Question 85 :

Describe Referential Integrity ?

Answer :

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.


Question 86 :

What is Hash Cluster ?

Answer :

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.


Question 87 :

What is a Private Synonyms ?

Answer :

A Private Synonyms can be accessed only by the owner.


Question 88 :

What is Database Link ?

Answer :

A database link is a named object that describes a "path" from one database to another.


Question 89 :

What is index cluster?

Answer :

A cluster with an index on the cluster key.


Question 90 :

What is hash cluster?

Answer :

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.


Question 91 :

When can hash cluster used?

Answer :

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.


Question 92 :

When can hash cluster used?

Answer :

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.


Question 93 :

What are the types of database links?

Answer :

Private database link, public database link & network database link.


Question 94 :

What is private database link?

Answer :

Private database link is created on behalf of a specific user. A private database link can be used only when the owner of the link specifies a global object name in a SQL statement or in the definition of the owner's views or procedures.


Question 95 :

What is public database link?

Answer :

Public database link is created for the special user group PUBLIC. A public database link can be used when any user in the associated database specifies a global object name in a SQL statement or object definition.


Question 96 :

What is network database link?

Answer :

Network database link is created and managed by a network domain service. A network database link can be used when any user of any database in the network specifies a global object name in a SQL statement or object definition.


Question 97 :

What is data block?

Answer :

Oracle database's data is stored in data blocks. One data block corresponds to a specific number of bytes of physical database space on disk.


Question 98 :

How to define data block size?

Answer :

A data block size is specified for each Oracle database when the database is created. A database users and allocated free database space in Oracle data blocks. Block size is specified in init.ora file and cannot be changed latter.


Question 99 :

What is row chaining?

Answer :

In circumstances, all of the data for a row in a table may not be able to fit in the same data block. When this occurs, the data for the row is stored in a chain of data block (one or more) reserved for that segment.


Question 100 :

What is an extent?

Answer :

An extent is a specific number of contiguous data blocks, obtained in a single allocation and used to store a specific type of information.