What is On-line Redo Log?

ORACLE Interview Questions and Answers (Part 4)

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678. 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.

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Other Interview Questions

• There is a string 120000 12 0 .125 , how you will find the position of the decimal place?
• What are different modes of parameters used in functions and procedures?
• How you were passing cursor variables in PL/SQL 2.2?
• When do you use WHERE clause and when do you use HAVING clause?
• Difference between procedure and function.?
• Which is more faster - IN or EXISTS?
• What is syntax for dropping a procedure and a function .Are these operations possible?
• How will you delete duplicating rows from a base table?
• Difference between database triggers and form triggers?
• What is a cursor for loop?
• How you will avoid duplicating records in a query?
• What is a view ?
• What is use of a cursor variable? How it is defined?
• How do you find the numbert of rows in a Table ?
• What is the maximum buffer size that can be specified using the DBMS_OUTPUT.ENABLE function?
• What are cursor attributes?
• There is a % sign in one field of a column. What will be the query to find it?
• What is ON DELETE CASCADE ?
• What is the fastest way of accessing a row in a table ?
• What is difference between TRUNCATE & DELETE ?
• What is a transaction ?
• What are the advantages of VIEW ?
• How will you a activate/deactivate integrity constraints ?
• Where the integrity constraints are stored in Data Dictionary ?
• What is the Subquery ?
• 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 ?
• What are the usage of SAVEPOINTS ?value in a session before accessing next value ?
• What is ROWID ?in a session before accessing next value ?
• Explain Connect by Prior ?in a session before accessing next value ?
• How many LONG columns are allowed in a table ? Is it possible to use LONG columns in WHERE clause or ORDER BY ?
• What is Referential Integrity ?
• What is a join ? Explain the different types of joins ?
• If an unique key constraint on DATE column is created, will it validate the rows that are inserted with SYSDATE ?
• How does one stop and start the OMS? (for DBA
• What is an Integrity Constraint ?
• How does one create a repository? (for DBA
• If a View on a single base table is manipulated will the changes be reflected on the base table ?
• The following describes means to create a OEM V1.x (very old!!!) repository on WindowsNT:
• What is a database link ?
• How does one list one's databases in the OEM Console? (for DBA
• What is CYCLE/NO CYCLE in a Sequence ?
• What is correlated sub-query ?
• What are the data types allowed in a table ?
• What is difference between CHAR and VARCHAR2 ? What is the maximum SIZE allowed for each type ?
• Can a view be updated/inserted/deleted? If Yes under what conditions ?
• What are the different types of Coordinations of the Master with the Detail block?
• Use the ADD_GROUP_COLUMN function to add a column to a record group that was created at design time? I) TRUE II)FALSE
• Use the ADD_GROUP_ROW procedure to add a row to a static record group? I) TRUE II)FALSE
• maxvalue.sql Select the Nth Highest value from a table?
• Find out nth highest salary from emp table?
• How you will avoid your query from using indexes?
• What utility is used to create a physical backup?
• What are the Back ground processes in Oracle and what are they.
• How many types of Sql Statements are there in Oracle
• What is a Transaction in Oracle
• Key Words Used in Oracle
• What are Procedure,functions and Packages
• What are Database Triggers and Stored Procedures
• How many Integrity Rules are there and what are they
• What are the Various Master and Detail Relation ships.
• What are the Various Block Coordination Properties
• What is in all those X$ tables? (for DBA
• What are the Different Optimisation Techniques
• How does one change an Oracle user's password?(for DBA
• How does one create and drop database users?
• Who created all these users in my database?/ Can I drop this user? (for DBA
• How does one enforce strict password control? (for DBA
• How does one switch to another user in Oracle? (for DBA
• What are snap shots and views
• What are the OOPS concepts in Oracle.
• What is the difference between candidate key, unique key and primary key
• What is concurrency
• Previleges and Grants
• Table Space,Data Files,Parameter File, Control Files
• Physical Storage of the Data
• What are the Pct Free and Pct Used
• What is Row Chaining
• What is a 2 Phase Commit
• What is the difference between deleting and truncating of tables
• What are mutating tables
• What are Codd Rules
• What is Normalisation
• What is the Difference between a post query and a pre query
• Deleting the Duplicate rows in the table
• Can U disable database trigger? How?
• What is pseudo columns ? Name them?
• How many columns can table have?
• Is space acquired in blocks or extents ?
• what is clustered index?
• what are the datatypes supported By oracle (INTERNAL)?
• What are attributes of cursor?
• Can you use select in FROM clause of SQL select ?
• Which trigger are created when master -detail rela?
• which system variables can be set by users?
• What are object group?
• What are referenced objects?
• Can you store objects in library?
• Is forms 4.5 object oriented tool ? why?
• Can you issue DDL in forms?
• What is SECURE property?
• What are the types of triggers and how the sequence of firing in text item
• Can you store pictures in database? How?
• What are property classes ? Can property classes have trigger?
• If you have property class attached to an item and you have same trigger written for the item . Which will fire first?
• What are record groups ? Can record groups created at run-time?
• What are ALERT?
• Can a button have icon and lable at the same time ?
• What is mouse navigate property of button?
• What is FORMS_MDI_WINDOW?
• What are timers ? when when-timer-expired does not fire?
• Can object group have a block?
• How many types of canvases are there.
• What are user-exits?
• Can you pass values to-and-fro from foreign function ? how ?
• What is IAPXTB structure ?
• Can you call WIN-SDK thruo' user exits?
• Does user exits supports DLL on MSWINDOWS ?
• What is path setting for DLL?
• How is mapping of name of DLL and function done?
• what is precompiler?
• Can you connect to non - oracle datasource ? How?
• What are key-mode and locking mode properties? level ?
• What are savepoint mode and cursor mode properties ? level?
• Can you replace default form processing ? How ?
• What is transactional trigger property?
• What is OLE automation ?
• What does invoke built-in do?
• What are OPEN_FORM,CALL_FORM,NEW_FORM? diff?
• What is call form stack?
• Can u port applictions across the platforms? how?
• What is a visual attribute?
• Diff. between VAT and Property Class? imp
• Which trigger related to mouse?
• What is Current record attribute property?
• Can you change VAT at run time?
• Can you set default font in forms?
• What is On-line Redo Log?
• Which parameter specified in the DEFAULT STORAGE clause of CREATE TABLESPACE cannot be altered after creating the tablespace?
• What are the steps involved in Database Startup ?
• What are the steps involved in Instance Recovery ?
• Can Full Backup be performed when the database is open ?
• What are the different modes of mounting a Database with the Parallel Server ?
• What are the advantages of operating a database in ARCHIVELOG mode over operating it in NO ARCHIVELOG mode ?
• What are the steps involved in Database Shutdown ?
• What is Archived Redo Log ?
• What is Restricted Mode of Instance Startup ?
• Can you have OLE objects in forms?
• Can you have VBX and OCX controls in forms ?
• What are the types of windows (Window style)?
• What is OLE Activation style property?
• Can you change the mouse pointer ? How?
• How many types of columns are there and what are they
• Can you have more than one layout in report?
• Can you run the report with out a parameter form ?
• What is the lock option in reports layout?
• What is Flex ?
• What are the minimum number of groups required for a matrix report
• What is a Synonym ?
• What is a Sequence ?
• What is a Segment ?
• What is schema?
• Describe Referential Integrity ?
• What is Hash Cluster ?
• What is a Private Synonyms ?
• What is Database Link ?
• What is index cluster?
• What is hash cluster?
• When can hash cluster used?
• When can hash cluster used?
• What are the types of database links?
• What is private database link?
• What is public database link?
• What is network database link?
• What is data block?
• How to define data block size?
• What is row chaining?
• What is an extent?
• What are the different types of segments?
• What is a data segment?
• What is an index segment?
• What is rollback segment?
• What are the uses of rollback segment?
• What is a temporary segment?
• What is a datafile?
• What are the characteristics of data files?
• What is a redo log?
• What is the function of redo log?
• What is the use of redo log information?
• What does a control file contains?
• What is the use of control file?