ERD to Data Structures Tutorial

ERD to Data Structures Tutorial - Logical Design Converting...

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Converting ERD’s to Data Structures Logical Design
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Life Cycle of a Database Data Developer User DBMS ProdID Name Desc Cost EmpID Last DOB Dept ProdID Name Desc Cost ProdID Name Desc Cost Database software Data stored in Database Structure of Data Tables Model of Data (ERD) SQL Requests Data Analysis Design Implementation Administrator Maintain, Modify, Use
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Important Concepts : Relation : A relation is a table that meets certain qualifications. The tables in our database will be relations. While all relations are tables, not all tables are relations--to be a relation, a table must meet certain qualifications. Properties of a Relation : Every row/column position, referred to as a cell, can only have a single value. When an attribute has only one value (it is not multivalued), it is said to be " atomic " Each column name is unique and the order of the columns in a relation is insignificant. The columns in a relation can be arranged in any order without affecting the meaning of the data. The order of the rows is insignificant. No two rows of a relation are identical. Entries in a column must be from the same domain . Domain : Set of all values that can be assigned to an attribute. Note that this definition addresses "meaning" as well as datatype. For example, Last Name and Address are both data type Character, but a column would not contain both names and addresses since these have different meanings.
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Start with the ERD! TIP: It is
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ERD to Data Structures Tutorial - Logical Design Converting...

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