MySQL characters commonly used segment and non-characters commonly used segment when building tables

A record of a pair of one by one tables must correspond only to one record in another table, and vice versa. Student table: Name, gender, age, height, weight, place of origin, home address, emergency contact name, gender, age, height, body weight is a common data, but the origin, address and contact person is not commonly used data if every query is to query all data, infrequently used data will affect efficiency, Not really the usual information table: ID (P), name, gender, age, height, weight not used information table: ID (P), hometown, home address, emergency contact solution: share the common and infrequently used information in storage, divided into two tables are not commonly used information tables and common information tables, Ensure that the non-common information table and the Common information table can correspond to: Find a unique field to connect two tables together. A record in a common table can always match only one record in one infrequently used table, and vice versa.

MySQL characters commonly used segment and non-characters commonly used segment when building tables