JOINS
Car Table
CarId
|
ModelYear
|
CarBrand
|
Model
|
Mileage
|
ModelYear
|
CarId
|
CA101
|
2008
|
Mahindra
|
Scorpio
|
15
|
2008
|
CA101
|
CA102
|
2009
|
Suzuki
|
800
|
12
|
2009
|
CA102
|
CA103
|
2007
|
Hundai
|
i20
|
5
|
2007
|
CA103
|
CA104
|
2007
|
Toyato
|
Inova
|
3
|
2007
|
CA104
|
CA105
|
2009
|
BMW
|
5
|
2009
|
CA105
| |
CA106
|
2010
|
Benz
|
AZ12
|
10
|
2010
|
CA106
|
RentalId
|
CustAccount
|
CarId
|
FromDate
|
ToDate
|
ToDate
|
FromDate
|
RE101
|
1104
|
CA101
|
10/12/2010
|
10/29/2010
|
10/29/2010
|
10/12/2010
|
RE102
|
1102
|
CA102
|
11/17/2010
|
12/14/2010
|
12/14/2010
|
11/17/2010
|
RE103
|
1203
|
CA103
|
11/24/2010
|
12/15/2010
|
12/15/2010
|
11/24/2010
|
RE104
|
1301
|
CA104
|
12/10/2010
|
1/5/2011
|
1/5/2011
|
12/10/2010
|
RE105
|
1304
|
CA101
|
1/3/2011
|
1/18/2011
|
1/18/2011
|
1/3/2011
|
RE108
|
1303
| |||||
RE107
|
1202
| |||||
RE106
|
2024
|
CA103
|
1/10/2011
|
1/29/2011
|
1/29/2011
|
1/10/2011
|
1. Inner Join : Records from main table that have matching record from join table .
while select carTable join rentalTable
order by carTable.CarId
where carTable.CarId == rentalTable.CarId ;
Output
2. Outer Join :
Select all records from main table and related records from join table
while select carTable outer join rentalTable
order by carTable.CarId
where carTable.CarId == rentalTable.CarId
3. Exists Join : Select record from main table only if there is matching record in join table .
while select carTable Exists join rentalTable
order by carTable.CarId
where carTable.CarId == rentalTable.CarId
4. Not Exists : Selecting record from main table only if there is not matching record in join table.
Link Types :
Delayed : A pause is inserted before linked child data sources are updated. This enables faster navigation in the parent data source because the records from child data sources are not updated immediately.
Active : The child data source is updated immediately when a new record in the parent data source is selected. Continuous updates consume lots of resources.
Passive: Linked child data sources are not updated automatically. Updates of the child data source must be programmed on the active method of the master data source
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