When we give SELECT * FROM EMP; How does oracle respond?

Categories >> Software >> Databases >> SQL PLSQL
Suggest New Category

Question Posted / pankit1515

24 Answers
50392 Views
Accenture, HCL, Infosys, I also Faced
E-Mail Answers

Answers were Sorted based on User's Feedback

When we give SELECT * FROM EMP; How does oracle respond?..

Answer / geetha priya

It will retrieve all the columns of emp table. There is no
need to check for conditions as there are no conditions
specified in the given command.

Is This Answer Correct ?

7 Yes

4 No

When we give SELECT * FROM EMP; How does oracle respond?..

Answer / babapps

hi

we enter this query then oracle engine takes this query and
to search particular given table in database table then
select command act as a cursor to retrieve the data or to
fetched the
data from database table then to print the data on sql prompt

Is This Answer Correct ?

4 Yes

2 No

When we give SELECT * FROM EMP; How does oracle respond?..

Answer / suresh

it will check for emp table(available or not).
1.if emp table available then it will retreive all the
colums from emp table..
2.if it is not available then it will give error..

Is This Answer Correct ?

2 Yes

0 No

When we give SELECT * FROM EMP; How does oracle respond?..

Answer / anand123

hI

I ama supporting Vaibhavi_dixit Answer.

Regards
Anand

Is This Answer Correct ?

3 Yes

2 No

When we give SELECT * FROM EMP; How does oracle respond?..

Answer / anupam a

Vaibhavi_dixit is close to correct

Is This Answer Correct ?

2 Yes

2 No

When we give SELECT * FROM EMP; How does oracle respond?..

Answer / umashankar

1.The PARSER scans/reads the SELECT statement and splits it
into some logical units such.
i.e: keywords/reserved word, operators, expressions and
identifiers.

2. SEQUENCE TREE or QUERY TREE is built the logical steps
needed to transform the source data into the format as
needed by the end result.

3. The QUERY OPRIMIZER analyzes the query in various ways
and selects the series of steps that returns the end
results fastest way. The query tree is updated to record
this exact series of steps. The final, optimized version of
the query tree is called the execution plan.

4. The RELATIONAL ENGINE starts executing the execution
plan which was prepared by the Query Optimizer.

5.The RELATIONAL ENGINE requests the STORAGE ENGINE pass up
data from the rowsets requested.

6. The RELATIONAL ENGINE processes the data (returns all
column values from EMP table) returned from the storage
engine to the client.

Is This Answer Correct ?

2 Yes

2 No

When we give SELECT * FROM EMP; How does oracle respond?..

Answer / venky

when we fire this query on

first it will send to sql buffer
then sql buffer send to SGA

sGA send to sql*plus layer

this layer interact with the database server if the table
is exist in the database server , it will dispatch the all
rows to sql*plus layer
from this layer to SGA-----> output buffer
..
finally it wii display on the location of interface(screen)

Is This Answer Correct ?

0 Yes

0 No

When we give SELECT * FROM EMP; How does oracle respond?..

Answer / d.elumalai

IF WE GIVE SELECT * FROM EMPLOYEES MEANS
THE ORACLE WILL DO THE FOLLOWING.

1.SYNTACTIC CHECK
2.SEMANTIC CHECK
3.HARD PARSING
4.SOFT PARSING

Is This Answer Correct ?

0 Yes

0 No

When we give SELECT * FROM EMP; How does oracle respond?..

Answer / wasim

User Level Process sends the query to Server level process
where in the query gets checked syntactically first. If the
syntax is correct then the query will get break down into
parts to evaluate what has to be done.

Oracle Engine then parses the query and understands that all
the rows from employee table has to be retrieved, before the
statement execution it will check whether the data is
available already in SGA. If its available then its will
send output to user, else it will execute the statement and
fetch the output from database and store it in database
buffers and then will pass on to user.

Is This Answer Correct ?

0 Yes

0 No

When we give SELECT * FROM EMP; How does oracle respond?..

Answer / ritesh goyal

When query is fired, Oracle will validate the syntax and semantics of the statement then creates a dynamic plan to execute it. retrieves the data from various datafiles and put it in an implicit cursor which is private SQL area for this query.

Is This Answer Correct ?

0 Yes

0 No

Post New Answer