StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
primarykey
Id
1493369
data
AcceptedAnswerId
0
AnswerCount
0
ClosedDate
CommentCount
2
CommunityOwnedDate
CreationDate
2009-09-29T15:40:15.843
FavoriteCount
0
LastActivityDate
2009-09-29T15:40:15.843
LastEditDate
LastEditorUserId
0
OwnerUserId
55159
ParentId
1493229
PostTypeId
2
Score
10
ViewCount
0
LastEditorDisplayName
text
Body
If we look into the model here, we will see the following: <ol> <li>A user is related to exactly one website <ul> <li>A company is related to exactly one website</li> <li>A website is related to exactly one user or company</li> </ul></li> </ol> The third relation implies existence of a "user or company" entity whose <code>PRIMARY KEY</code> should be stored somewhere. To store it you need to create a table that would store a <code>PRIMARY KEY</code> of a <code>website owner</code> entity. This table can also store attributes common for a user and a website. Since it's a one-to-one relation, website attributes can be stored in this table too. The attributes not shared by users and companies should be stored in the separate table. To force the correct relationships, you need to make the <code>PRIMARY KEY</code> of the <code>website</code> composite with <code>owner type</code> as a part of it, and force the correct type in the child tables with a <code>CHECK</code> constraint: <pre><code>CREATE TABLE website_owner ( type INT NOT NULL, id INT NOT NULL, website_attributes, common_attributes, CHECK (type IN (1, 2)) -- 1 for user, 2 for company PRIMARY KEY (type, id) ) CREATE TABLE user ( type INT NOT NULL, id INT NOT NULL PRIMARY KEY, user_attributes, CHECK (type = 1), FOREIGN KEY (type, id) REFERENCES website_owner ) CREATE TABLE company ( type INT NOT NULL, id INT NOT NULL PRIMARY KEY, company_attributes, CHECK (type = 2), FOREIGN KEY (type, id) REFERENCES website_owner ) </code></pre>
Tags
Title
singulars
PostAcceptedAnswerId
1. This table or related slice is empty.
PostParentId
1. POMultiple yet mutually exclusive foreign keys - is this the way to go?
 singulars
 PostTypePostTypeId
 PTQuestion
PostTypePostTypeId
1. PTAnswer
UserLastEditorUserId
1. This table or related slice is empty.
UserOwnerUserId
1. USQuassnoi
plurals
PostLinksPostIdRelatedPostId
1. This table or related slice is empty.
PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. POMultiple yet mutually exclusive foreign keys - is this the way to go?
 singulars
 PostTypePostTypeId
 PTQuestion
PostsParentIdCreationDate
1. This table or related slice is empty.
VotesPostIdCreationDate
1. VO
 singulars
 PostPostId
 PO
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTUpMod
2. VO
 singulars
 PostPostId
 PO
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTAcceptedByOriginator
3. VO
 singulars
 PostPostId
 PO
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTUpMod
CommentsPostId
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.