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• How would you conduct a test: top-down or down-top? What is it? Which one is better?

  
  
  Down-Top: unit -> interface -> system. Top-Down is a vice versa. You may use both, but down-top allows to discover malfunctioning at earlier phases of development and cheaper to fix than in the case of top-down.

• What is defect density ?

  
  
  defect density = Total number of defects/LOCHere the Total number of defects include the defects from Review.

• What is SYNCHRONIZE?

  
  
  Synchronizes the terminal screen with the internal state of the form. That is SYNCHRONIZE updates the screen display to reflect the information that Oracle Forms has in its internal representation of the screen.

• What is the difference between Object Embedding and Linking in Oracle Forms

  
  
  Linking in Oracle Forms? An Ole server applications creates OLE objects that are embedded or linked in OLE containers. Examples of OLE servers are MS Word and MS Excel. OLE containers provide a place to store,display and manipulate objects that are created by OLE server applications.

• How do you create a new session while opening a new form?

  
  
  Using OPEN_FORM built-in setting the SESSION option. Ex: OPEN_FORM(??STOCKS??,ACTIVE,SESSION); When you invoke multiple forms with OPEN_FORM and CALL_FORM in the Same application,state whether the following are TRUE or FALSE

• What are the built-ins used for finding Object ID functions?

  
  
  FIND_GROUP(function) FIND_COLUMN(function)

• What are the built-ins used for processing rows?

  
  
  GET_GROUP_ROW_COUNT(function) GET_GROUP_SELECTION(function) GET_GROUP_SELECTION(function) RESET_GROUP_SELECTION(Procedure) SET_GROUP_SELECTION(Procedure) UNSET_GROUP_SELECTION(Procedure)

• What are the built-ins used for getting cell values?

  
  
  GET_GROUP_CHAR_CELL(function) GET_GROUP_DATE_CELL(function) GET_GROUP_NUMBER_CELL(function)

• List the factors that can affect the accuracy of the estimations?

  
  
  The space used transaction entries and deleted records does not become free immediately after completion due to delayed cleanout. Trailing nulls and length bytes are not stored. Inserts of, updates to, and deletes of rows as well as columns larger than a single data block, can cause fragmentation and chained row pieces.

• What are disadvantages of having raw devices?

  
  
  We should depend on export/import utility for backup/recovery (fully reliable) The tar command cannot be used for physical file backup, instead we can use dd command which is less flexible and has limited recoveries.

• What a hit ratio?

  
  
  When Segment is dropped. When Shrink (RBS only) When truncated (TRUNCATE used with drop storage option)

• What is a Rollback segment entry?

  
  
  It is the set of before image data blocks that contain rows that are modified by a transaction. Each Rollback Segment entry must be completed within one rollback segment. A single rollback segment can have multiple rollback segment entries.

• What is meant by Redo Log file mirroring ? How it can be achieved?

  
  
  Process of having a copy of redo log files is called mirroring. This can be achieved by creating group of log files together, so that LGWR will automatically writes them to all the members of the current on-line redo log group. If any one group fails then database automatically switch over to next group.

• How to implement the multiple control files for an existing database?

  
  
  Shutdown the database Copy one of the existing control file to new location’ Edit config.ora file by adding new control file name Restart the database

• What is a control file?

  
  
  Database’s overall physical architecture is maintained in a file called control file. It will be used to maintain internal consistency and guide recovery operations. Multiple copies of control files are advisable.

• Is it possible to use raw devices as data file and what is the advantages over file system files?

  
  
  Yes.The advantages over file system files : I/O will be improved because Oracle is bye-passing the kernal while writing into disk. Disk Corruption will be very less.

• How will you estimate the space required by non-clustered tables?

  
  
  Calculate the total block header size Calculate the available data space per block Calculate the combined column length of the average row Calculate the total average row size Calculate the average number rows that can fit in a block Calculate the number of blocks and bytes required for the table After arriving the calculation add the additional space to calculate the [...]

• How can we plan storage for very large tables?

  
  
  Limit the number of extents in the table Separate the Table from its indexes Allocate sufficient temporary storage

• List the sequence of events when a large transaction that exceeds beyond its optimal value when an entry wraps and causes the rollback segment to expand into another extend?

  
  
  Transaction Begins An entry is made in the RBS header for new transactions entry Transaction acquired blocks in an extent of RBS The entry attempts to wrap into second extent. None is available. So that the RBS must extent. The RBS checks to see if it is oldest inactive segment Oldest inactive segment is eliminated RBS extends The Data dictionary table for [...]

• How will you monitor rollback segment status?

  
  
  Querying the DBA_ROLLBACK_SEGS view The status available as follows : IN USE - Rollback Segment is on-line AVAILABLE - Rollback Segment available bur not on-line OFF-LINE - Rollback Segment us off-line INVALID - Rollback Segment dropped NEEDS RECOVERY - Contains data but need recovery or corrupted PARTLY AVAILABLE - Contains data from an unresolved transaction involving a distributed database