Databases
StackOverflow2013
Postsdbo
POInheritance in Database Design
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POInheritance in Database Design
    primarykey
    data
    text
    <p>I am designing a new laboratory database with MANY types of my main entities.</p> <p>The table for each entity will hold fields common to ALL types of that entity (entity_id, created_on, created_by, etc). I will then use concrete inheritance (separate table for each unique set of attributes) to store all remaining fields.</p> <p>I believe that this is the best design for the standard types of data which come through the laboratory daily. However, we often have a special samples which often are accompanied by specific values the originator wants stored.</p> <p><strong>Question:</strong> How should I model special (non-standard) types of entities?</p> <p><strong>Option 1:</strong> Use entity-value for special fields<br/> One table (<code>entity_id</code>, <code>attribute_name</code>, <code>numerical_value</code>) would hold all data for any special entity.<br/> + Fewer tables.<br/> - Cannot enforce requiring a particular attribute.<br/> - Must convert (pivot) rows to columns which is inefficient.<br/></p> <p><strong>Option 2:</strong> Strict concrete inheritance.<br/> Create separate table for each separate special case.<br/> + Follows in accordance with all other rules<br/> - Overhead of many tables with only a few rows.<br/></p> <p><strong>Option 3:</strong> Concrete inheritance with special tables under a different user.<br/> Put all special tables under a different user.<br/> + Keeps all special and standard tables separate.<br/> + Easier to search for common standard table in a list without searching through all special tables.<br/> - Overhead of many tables with only a few rows.<br/></p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USSteven
    1. USSteven
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POInheritance in Database Design
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POInheritance in Database Design
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POInheritance in Database Design
      1. This table or related slice is empty.
      1. VTUpMod
    1. COMany tables with a few rows are likely to perform better than an entity-value table especially when it gets large. And they are far easier to query.
      singulars
      1. POInheritance in Database Design
      1. USHLGEM
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload