BDP reading notebook 1

发布时间：2020-12-13 17:59:54 所属栏目：百科来源：网络整理

导读：Beginning Database with PostgreSQL reading notebook 1 flat files : repeating groups spreadsheets : can not support multiuser access ; strict two deminsions basic rules for designing tables : 1. break down the data into columns 2. have a uni

Beginning Database with PostgreSQL reading notebook 1 flat files : repeating groups spreadsheets : can not support multiuser access ; strict two deminsions basic rules for designing tables : 1. break down the data into columns 2. have a unique way of identify each row 3. remove repeating information 4. get the naming right with n2n relationship create a third table bettwen the two tables Date Types : serial,char,varchar,date,numeric specially notice the NULLs

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