6. Relational Design Basics contd…. Entity – Relationship Model ER model is a conceptual data model that views the real world as entities and relationships. Entities - Entities are the principal data object about which information is to be collected. e.g . Employee, Department etc. Attributes - Attributes describe the entity of which they are associated. A particular instance of an attribute is a value . e.g . Employee can have attributes like Employee Name, Employee Number etc. Relationships – Relationship represents an association between two or more entities.
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18. Database Objects Tables Constraints Indexes Rules Views Defaults Data Types Stored Procedures Triggers User Defined Functions Database Objects
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32. JOIN Keyword - FULL Outer Join SELECT * FROM Employees AS E FULL OUTER JOIN Departments AS D ON E.deptno = D.deptno NULL 30 20 10 JobID Engineering 300 NULL NULL NULL NULL NULL 1500 Jeffrey 3 Deptname Deptno Salary Empname Empid Management 200 2000 Bob 2 Production 100 1000 Leo 1