Databases
StackOverflow2013
Postsdbo
POMySQL relations for country region and town tables
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POMySQL relations for country region and town tables
    primarykey
    data
    text
    <p>I am trying to figure out the best method to relate country, region and town tables.</p> <p>On my website I want the user to be able to just enter a town. Then optionally country and region, both of which will be required to be entered or not at all.</p> <p>Currently my tables are as such</p> <blockquote> <p>tbl&gt;User has townID (FK)</p> <p>tbl&gt;town has id(PK) townName regionID(FK DEFAULT NULL)</p> <p>tbl&gt;region has id(PK) regionName countryID(FK NOT NULL)</p> <p>tbl&gt;country has id(PK) countryName</p> </blockquote> <p>I thought to possibly further spit the user to town relation to:</p> <blockquote> <p>tbl&gt;User has locationID (FK)<br> tbl&gt;location has id (PK) townID(FK) regionID(FK) countryID(FK)</p> </blockquote> <p>But I think that is unnecessary and just further complicates the issue?</p> <p>The country database is already populated. I intend to build up my own references of town > region > country relations as entered by users. So if a user enters a town with no region and country then it is entered into tbl>town without a regionID if there isn't already a town with the same name without a region ID. This is same for a town where a region and country ID has been entered by the user. Only I check that there isn't already a town > region > country relation that already exists before entering. Later on in the development of the site I will be providing Ajax suggestions for country/region based upon the town entered by a user.</p> <p>So to the questions:</p> <p>I can envisage pitfalls with this such as duplicate data or data possibly being overwritten. Is there a better way to construct the tables to fit in with my desired methods?</p> <p>This might get answered by the prior question: but is there anything I can do to reduce the PHP processing of the tables. Obviously I'd prefer to just insert with one PHP statement but I think there are too many caveats to do it at once.</p> <p>Also as the users town entry may be null and may or may not contain a foreign key reference to a region how is it best to create a View that takes that into consideration?</p> <p>As it will be hosted I would rather not be using MySQL functions.</p> <p>Please let me know if you need any clarification. I really want to get this right the first time before continuing, so your help will be invaluable.</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USPeter Mortensen
    1. USCraig Stewart
    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. This table or related slice is empty.
    1. This table or related slice is empty.
 

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