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wahidullah
Starting Member
5 Posts |
 Posted - 2013-05-15 : 08:14:32
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| Hi, while developing a database, Is it necessary to create the number of tables equal to the number of entities?thanks!wahidullah290 |
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visakh16
Very Important crosS Applying yaK Herder
52326 Posts |
Posted - 2013-05-16 : 00:41:31
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| nope. Although most cases there will be 1-to -1 mapping. There can be cases where entity can be broken up into multiple tables when applying normalisation etc------------------------------------------------------------------------------------------------------SQL Server MVPhttp://visakhm.blogspot.com/https://www.facebook.com/VmBlogs |
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wahidullah
Starting Member
5 Posts |
Posted - 2013-05-16 : 06:36:16
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| if we dont create table for an entity, can we remove it from the ERD?wahidullah290 |
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visakh16
Very Important crosS Applying yaK Herder
52326 Posts |
Posted - 2013-05-16 : 06:42:39
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| hmm..Why is it that you dont need to create table if its already identified as an entity?My point was inverse condition ie having more than one tables to represent same entity. I cant think of a case where you wont have a table for an already identified entity------------------------------------------------------------------------------------------------------SQL Server MVPhttp://visakhm.blogspot.com/https://www.facebook.com/VmBlogs |
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wahidullah
Starting Member
5 Posts |
Posted - 2013-05-19 : 10:26:51
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| dear visakh:I meant, is it necessary to create tables for each entity in the ERD?if your answer is possitive then tell me the solution. I create ERD for a hospital and the reference relationship became the associative entity in this case I dont need to create table for reference. is it right?wahidullah290 |
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visakh16
Very Important crosS Applying yaK Herder
52326 Posts |
Posted - 2013-05-20 : 01:13:20
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| 1. it is2. reference relationship will ideally be represented by means of mapping table.------------------------------------------------------------------------------------------------------SQL Server MVPhttp://visakhm.blogspot.com/https://www.facebook.com/VmBlogs |
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ERD and Table