Basic Computer Notions Databases

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Relational examples (cont'd)

Example relational tables

Question #1: What is average weight of babies delivered by Jones to mothers with heights > 170 cm?

Here are the 3 projected columns.
PhName MHt M#
Smith 150 123456
Jones 177 392382
Smith 162 238427
Smith 174 649308
Jones 155 732293

Next we Select the records with PhName = Jones and MHt > 170.

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Last modified: Wed, 2007 Mar 21 17:29:21

Slide show generated from dbms.html by Weasel 2007 Mar 21