what is primary key,unique key, foreign key? can u teach me
in simple language?
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Answer Posted / mohamed ibrahim
Primary Key :- Is a unique identify a table data,it is avoid null and duplicate value.In a table we can assign single primary key.
Unique Key :- Is same as primary key but it allow single null value and avoid duplicate value.In a table we can assign more than one no of unique key.
Foreign Key :- Is a connect two table from a single column name.
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Source File: Target EMPNO, SAL Empno, Format 101, 1000 101, 1000 101, 1100 101, 1000, 1100 101, 1000 101, 1000, 1100, 1000 101, 10000 101, 1000, 1100, 1000, 10000 102, 1100 102, 1100 102, 1300 102, 1100, 1300 102, 1200 102, 1100, 1300, 1200 102, 1500 102, 1100, 1300, 1200, 1500 How can i get that output using datastage(ETL) tool
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