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Written by Administrator
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Tuesday, 24 March 2009 14:34 |
Table has rows and columns.
You can imagine table as a spreadsheet with rows and columns. At the intersection of rows and columns, there are cells.
Cells contain values.
A table stores information about entities e.g. Employee, Department etc.
Something of importance is referred to as entities.
The columns of the table represent attributes of the entity. For example Name, Salary, Department Number etc are attributes of an Employee.
Each record (or row) of the table represents an instance on the entity. For example Scott and Larry.
No two rows could be the same. That is why there are ID columns in tables. ID columns contain incremental values like 1,2,3 etc. This create uniqueness for each row. Each value represent distinct instance of the entity.
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