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Fields: Smallest unit in a table

Records: collections of fields or columns

Table: Collections of fieldsPrimary Key: A primary key has a immutable responsibility of serving a unique identifier

in a table.

Foreign Key: Is a column that refers to a primary key in another table.Composite Index: more than one column are included to make primary key

Database: Collections all the tables and objects are called database

DBA: The integrity, security, connectivity, performance, tuning, ensuring the recovery ofthe database is maintained by DBAs. They use oracle enterprise management tools to do

the task.

Developers: They use tools like forms, reports, graphics for front-end development,

schema, procedure, query builder tools for back end. Project builder tools for delivery toclients.

A table can have unique keys, composite keys, primary keys, foreign keys. Avoid having

too many keys on the table.

Joins: Joining two or more tables is the best use of relational databaseINNER JOIN OR EQUI JOIN

Cartisian Product: xOuter Join: Matching + unmatched Records

If Join keyword is used in the query then On key word condition is used or else Where

condition: only for natural join on key, where is not required

Usingdisplayes only one caolumnOn displays all the common columns

Using = On(are interchangeable

A correlated sub-query is a term used for specific types ofqueries inSQL in computerdatabases. It is a sub-query (a query nested inside another query) that uses values from

the outer query in its WHERE clause. The sub-query is evaluated once for each rowprocessed by the outer query.

Employees with their managers

Select e.empno, e.ename, e.mgr , m.empno, m.ename from emp e, emp m where e.mgr =

m.empno;

Escape Character queriesIf the escape character is & then to find %, _ in the string use the querySELECT * FROM emp WHERE ename LIKE '%^_%^%%' ESCAPE '^'

insert into emp1 (ename) values ('IMRAN&BAIG%1_2#')

NOTE: Error it will ask for value of baig

If you want to insert & in the field then

From sql> prompt set define off then insert statement

This will work.

http://en.wikipedia.org/wiki/Query_languagehttp://en.wikipedia.org/wiki/SQLhttp://en.wikipedia.org/wiki/SQLhttp://en.wikipedia.org/wiki/Databasehttp://en.wikipedia.org/wiki/Where_(SQL)http://en.wikipedia.org/wiki/Query_languagehttp://en.wikipedia.org/wiki/SQLhttp://en.wikipedia.org/wiki/Databasehttp://en.wikipedia.org/wiki/Where_(SQL)

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SQL Loader:

LOAD DATA

INFILE path or *(if the data is given using BEGINDATA key in the ctl file at the

end)

APPEND/INSERT/REPLACE INTO TABLE table_nameFIELDS TERMINATED BY , OPTIONALLY ENCLOSED BY

(

column_name1 [position(value1:value2) if begindata is used] ,

column_name2 [position(value1:value2) if begindata is used] ,

column_name3 [position(value1:value2) if begindata is used] ,

.

.

.

)

[([] means optional)

BEGINDATAColumn1_value Column2_value Column3_value(give exact positions)

]

TRAILING NULLCOLS will allow null values into the table columns

BELOW is an example

If values are giving using begindata then null values can be passed by giving , withoutvalues like ename, empno, , sal

If values are freom the data file then no need

LOAD DATA INFILE

*

APPEND INTO TABLE emp1FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'

TRAILING NULLCOLS(

empno,

ename,

sal,comm,

deptno

)

BEGINDATA

2222, "IMRAN BAIG", ,22, 203222, "IMRAN,BAIG", 3222, 32, 20

4222, "IMRAN&BAIG", 4222, 42, 30

Exists Operator

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If the sub-query returns data, then the EXISTS operation will return TRUE and a record

from the parent query will be returned.