Sunday, September 11, 2011

STEP—3: Insert Joins

Insert Joins
To display the Joins between Tables in Universe Structure Panel use following Navigations
1)    Manual Join
----à Without selecting a Table drag a table column [Article_ID of Article_lookup] in to corresponding column of second table [Article_ID of Article_color_lookup]
----à Double click on Applied Join [link]
----àClick on Detect to find the Cardinality
----àClick on OK
2)    Insert Menu Join
----àClick on Insert Menu ----àJoin
          It opens Edit Join Interface
----à  Select the First table as Article_lookup
----à  Select the Second table as Article_lookup_criteria
----à  Select Article_ID between the two tables
----àClick on Detect
----àClick on OK
3)    Auto Detecting Joins
----à Click on Tools menu----àAutomated Detections----àDetect Joins
          It displays the possible Joins from Universe Structure Panel.
----àSelect the Required Joins----àClick on Insert.
For Detecting Joins we need to depend on Detect Cardinalities to Apply Data Relationships.
    ----àClick on Tools menu
    ----àAutomated detection
    ----àDetect Cardinalities
1)    How many types of joins can be applied from Universe?
Ans: There are 5 types of joins
1)    Inner Join [Equi Join]
2)    Left Outer Join
3)    Right Outer Join
                      [Full Outer Join is not supported by Universe]
4)    Theta Join
5)    Shortcut Join
Inner Join: If the Join condition is applied with only = [equal to] operator is called       as Inner Join or Equi Join
Using this property only common data of two tables is returned.
Right Outer Join: In the Edit join screen if Left side Outer join is selected it is treated as Right Outer Join
Internally it returns common data between the two tables and all extra records in Right Table.
Left Outer Join: In Edit Join screen, if the Right side Outer Join is selected it is treated as Left Outer Join
Using this property, it returns common data between the two tables and all extra records in Left Table.
Theta Join: While applying the join condition if we select other than to Equal operator then it is called as Theta Join or Non-Equi Join
Shortcut Join: This property is recommended to resolve the Loop by applying Second Priority for the Joins.

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