Daily Report

Task Summary

  • Organizing and analyzing the results of experiments to be written for the paper.
  • Routine task
    • Learning English



  • SQL Antipattern 5
    • EAV (Entity Attribute Value)
      • Context won’t be fixed until reading WHERE statement
      • Can not set required column
      • Can not use data type
      • Can not use aggression function
      • Can not mandate referential integrity
      • The attribute name must be complemented
      • When “OUTER JOIN” statement is multiply used on in one query, the time complexity will become exponential.
      • The number of tables that MySQL 5.6 can reference at one time is 61.
      • The maximum number of columns that a table can have is 4096.
    • Solution to adopting EAV
      • Single table inheritance
        • Add columns which is used by only certain attribute.
      • Concrete Table Inheritance
        • This is appropriate when searches across all subtypes are performed infrequently.

Interruption at work

  • nothing

Coding Test


Takizawa Tetsu
Takizawa Tetsu