Alias table means it is a reference table for the physical Table. When you create any alias table, then the alias table will inherit all the properties of the physical table.
We can not modify the alias table properties, like
1. can not rename the column name.
2. Can not change the column data type .
3. Can not delete the columns
But we can only change the alias table name according to our naming convention.
Steps to create Alias table :
1. Right click on the physical table, New Object -->Alias
2. Give the name for alias table. Then click on OK.
Advantages of Alias Table :
1. OBIEE does not support Circular join in BMM layer, so we can overcome from this problem by creating alias table for one of the table in that circular join.
2. OBIEE does not support self join, so we can overcome from this problem by creating alias table.
3. If a fact table having relationship with dimention table on more than one key, then we can create aliases for the dimension talbe, then we can join fact table to these alias table on different keys.
Eg : consider, there is a order table, it has two columns in that, namely, order_date and required_date, both columns have to be joined to the Time dimension. In such situation we can create alias for the Time dimension, like Order_Date_dim and Required_date_dim. Now join the order table to these tables on different keys.
We can not modify the alias table properties, like
1. can not rename the column name.
2. Can not change the column data type .
3. Can not delete the columns
But we can only change the alias table name according to our naming convention.
Steps to create Alias table :
1. Right click on the physical table, New Object -->Alias
Advantages of Alias Table :
1. OBIEE does not support Circular join in BMM layer, so we can overcome from this problem by creating alias table for one of the table in that circular join.
2. OBIEE does not support self join, so we can overcome from this problem by creating alias table.
3. If a fact table having relationship with dimention table on more than one key, then we can create aliases for the dimension talbe, then we can join fact table to these alias table on different keys.
Eg : consider, there is a order table, it has two columns in that, namely, order_date and required_date, both columns have to be joined to the Time dimension. In such situation we can create alias for the Time dimension, like Order_Date_dim and Required_date_dim. Now join the order table to these tables on different keys.
Nice Post
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