Primary Key:
----------------
1) Should be Unique and not null.
2) Mainly used for Referential Integrity.
3) While creating table only primary key is mentioned and there is no primary index mentioned .Instead of first column the primary key column will be taken as unique Index.
Primary Index:
------------------
1) Could be Unique or Non Unique
2) Mainly used for Data Distribution and Data retrieval in Teradata.
3) Null values are allowed
4) Choosing wrong primary index leads to data skew/Amp Skew.
----------------
1) Should be Unique and not null.
2) Mainly used for Referential Integrity.
3) While creating table only primary key is mentioned and there is no primary index mentioned .Instead of first column the primary key column will be taken as unique Index.
Primary Index:
------------------
1) Could be Unique or Non Unique
2) Mainly used for Data Distribution and Data retrieval in Teradata.
3) Null values are allowed
4) Choosing wrong primary index leads to data skew/Amp Skew.
No comments:
Post a Comment