What is a join? Explain different types of joins?

Answers were Sorted based on User's Feedback



What is a join? Explain different types of joins?..

Answer / nareshkumar

A join is a condition that links the data in seperate but
related tables. The tables usually have a parent-child
relationship. If a query does not contain a join, the
database returns a result set that contains all possible
combinations of the rows in the query tables.

Types of joins:

1) Equi-Joins
Link tables based on the equality between the values in the
column of one table and the values in the column of another.

2) Theta Joins
Link tables based on a relationship other than equality
between two columns.

3) Outer Joins (Left Outer, Right Outer, Full Outer)
Link two tables, one of which has rows that do not match
those in the common column of the other table.

4) Shortcut Joins
Join providing an alternative path between two tables,
bypassing intermediate tables, leading to the same result,
regardless of direction. Optimizes query time by cutting
long join paths as short as possible.

5) Self restricting joins
Single table join used to set a restriction on the table.

Is This Answer Correct ?    24 Yes 4 No

What is a join? Explain different types of joins?..

Answer / subhash

Join is used to link to tables depending upon the data
requested by the user, Usually we have Inner Join, Outer
Join, Left Join, Right Join, Full Outer join.

Is This Answer Correct ?    14 Yes 5 No

What is a join? Explain different types of joins?..

Answer / vams_gk

join is very imp concept in BO

relation between two tables is called joins.
we have 4 types of join relations 1:m,m:1,m:m,1:1

types of joins in BO
1)equi join
2)theta join
3)outer join(left/right)
4)isolated join
5)short cut join

Is This Answer Correct ?    11 Yes 2 No

What is a join? Explain different types of joins?..

Answer / venkatesh

Hi everybody,

whatever NareshKumar explained about the joins is right
except the Shortcut join.

4) Shortcut Joins
Join providing an alternative path between two tables,
bypassing intermediate tables, "leading to the same result,
regardless of direction". Optimizes query time by cutting
long join paths as short as possible.

In the above defination (which is mentioned in the inverted
commas)the result wont be same. It is different.

Example:
There is 4 tables
A,B,C,D

The join in between these 4 tables are like this.

A--B--C--D

Here if I drag A and D tables then I will get 6 rows for
example.

Now Make a shortcut join between A and D

Now if I drag A and D tables then I will get more than 6
rows.Why because

In first join the data is filtering from A to D like below
First A to B then B to C after that C to D.

But in Shortcut there is direct join A to D.Here the data
is not filtering.

Thanks,
Venky

Is This Answer Correct ?    5 Yes 3 No

What is a join? Explain different types of joins?..

Answer / srinu

Combining a data from multiple tables is called join.
There r 5 types of joins r there.
1)Simple join 2)Equi join 3)Outer join 4)Theta join
5)Short cut join

Is This Answer Correct ?    4 Yes 11 No

Post New Answer

More Business Objects Interview Questions

wat is difference b/w break and section?

4 Answers  


how many user were there

1 Answers  


When a report in Web intelligence is created with ten objects and save the same as PDF the report divides the report into two pages. One page with data for five objects and the other with next five objects? Is there a way to combine these ten columns in a single page view?

2 Answers  


how to do scheduling in desktop intelligence in BO XI R2

3 Answers  


I have 2 tables. Table 1 is employee table and Table2 is department table. In employee table i have 1,2,3,4,5 emp id's,in Dept table i have various dept's like a,b,c and i have 2,3,4 emp id's in my dept table.I joined with these 2 tables.I want the results for equi join means how many records will fetch.In the same scenario i have to know the left outer join, right out join and full outer join resuls means how many records will come. can any body tell me the answers

1 Answers   IBM,






WHAT ARE THE META DATA TYPES?WHICH META USING IN BO'S

0 Answers  


What is the @script and @variable functions in the universe designer ? can anybody explain me in a simple way?

2 Answers   CTS,


Can any body tell me,What is the universe testing ? What is the report testing Explain?

2 Answers  


Hi I am starter in BOXIR2.CAn anyone plz tell me the user identification details to be entered at the time of login to designer/deski

1 Answers  


normally we get many contexts when resolving loops or traps,how do u take them to reports.

2 Answers   Wipro,


how can u find the granularity in fact table

1 Answers   iGate,


What is the use of Surrogate key in BO?

8 Answers   IBM,


Categories