The evolution of database systems is as follows

File Management System
Hierarchical database System
Network Database System
Relational Database System

File Management System:
The file management system also called as FMS in short is one in which all data is stored on a single large file. The main disadvantage in this system...

SQL injection is one of the security abuse in which the person makes use of SQL in other words Structured Query Language in a web form in order to have access to data and thereby make changes to the data. That is on a web application the user has to be validated with username and password and only if it matches they must gain access to the database. This is the main security action that has to be followed...

A junction record is one which allows many to many relationship between the two owner records. One of the scenario in which junction table plays a role in Microsoft Access is while creating or defining many to many relationship. Many to Many relationships between two entities are one in which one row or record of a table can relate to many records in other table and also vice-versa for the other table....

COUNT is a group function. That is which gives a result by summarizing multiple rows. All group value function will have the usage of DISTINCT or ALL option and so is the COUNT which uses the DISTINCT option. DISTINCT option is used to enforce uniqueness and this combined with COUNT is used to count only unique mentioned value.
To understand this let us see an example. Consider a table exforsys...

Tuning is one of the main function or job of a database administrator or DBA in short. This is because oracle is a relational database management system which is tunable and thus the database can be monitored and therefore appropriate measures and steps can be taken at appropriate times to increase the performance of the system. There are many reasons for performing the performance tuning in oracle....

DECODE is used to decode a CHAR or VARCHAR2 or NUMBER into any of several different character strings or numbers based on value. That is DECODE does a value-by-value substitution. For every value that is given in the DECODE function it makes an if then check and matches the value. The general format of DECODE function is given below:

DECODE(value,if1,then1,if2,then2,……,else)...

E.codd designed 12 rules that stated rules for database to be relational. These rules were named as codd’s rules. The rules are given below: 1. The Information Rule: For a database to be relational all information is represented as data values in tables. 2. The Rule of Guaranteed Access: The data represented in table by using table name, column name and primary key value defined for that table....

srinivas devulapalli

• Sep 12th, 2006

Toad Tool exist in not only importing or exporting the data but also creating the database objectthe object etc

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kumaresan.m

 Profile Answers by kumaresan.m Questions by kumaresan.m

• Sep 12th, 2006

high water mark is concerned with segments not with the datafilesafter analysing the segments, this query will give the hwm for the segmentselect (blocks-empty_blocks) HWM from dba_segments where segment_name=upper('name') and segment_owner=upper('name');

bhanushiva

 Profile Answers by bhanushiva Questions by bhanushiva

• Jan 19th, 2006

There is no single system table which contains the high water mark (HWM) for a table. A table's HWM can be calculated using the results from the following SQL statements: SELECT BLOCKS ...

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developer

• Sep 11th, 2006

Hi,The correct answer isselect to_char(to_date(15000,'j'),'jsp') from dual;try this one. hope this will help u.byedevp2.

satya

• Sep 6th, 2006

I think it is correct , there is no word called Lakh in US English. Try switch to language UK english then it may work.    Lot of people in USA dont understand certain UK english words.

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Suman

• Sep 7th, 2006

Hi,   Could you please tell me more clearly on "Grid Technology" and how it is  different from other Oracle version say,Oracle 9i?Thanks in advance.     &n...

Nishanth

• Aug 17th, 2006

The g in ORACLE 10g means GRID TECHNOLOGY10g is Oracle's grid computing product group including (among other things) a database management system (DBMS) and an application server.

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Murugavel

• Aug 29th, 2006

Hi,I hope the difference is:execute() - returns boolean value (true implies that the query returns some Resultset, where false is not)executeUpdate() - returns integer value (the value implies number of rows affected)bye..

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srinivas

• Aug 24th, 2006

If we have same triggers at form level, block level and item level, then the triggers at lowest level will take first priority. so the sequence is item level, block leven and form level.

Cnu

• Mar 18th, 2006

The default execution hierachy is Item-levelBlock-LevekForm-LevelIf u want to change the execution Hierarchy u can set the trigger property from override to Before or After as per ur requirement.Regards.,Cnu.,

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lax

• Aug 22nd, 2006

A candidate key is a key that uniquly identifies

sandeep kumar

• Jan 16th, 2006

key is the attribute that can uniquely identify specified record from  a table. Any key i.e. attribute or combination of attributes can be selected as primary key. the remaining key attributes ar...

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Padmanathan

• Aug 20th, 2006

Hi,select owner, segment_name,bytes/1024/1024 "Size in Mb" from dba_segments where segment_type=<TABLE_NAME>This is total size physicall occupiedfor actual size:Analyze the table first using DBM...

harsha

• May 11th, 2006

How to get the size of the specified table i.e for a particular table??

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