StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
primarykey
Id
8618779
data
AcceptedAnswerId
0
AnswerCount
0
ClosedDate
CommentCount
0
CommunityOwnedDate
CreationDate
2011-12-23T17:10:33.993
FavoriteCount
0
LastActivityDate
2011-12-23T17:10:33.993
LastEditDate
LastEditorUserId
0
OwnerUserId
217862
ParentId
8617603
PostTypeId
2
Score
2
ViewCount
0
LastEditorDisplayName
text
Body
You are asking a lot here :) Type system is a dedicated field of computer science! Starting from the begining, "a type system is method for proving the absence of certain program behavior" (See <a href="http://www.cis.upenn.edu/~bcpierce/tapl/" rel="nofollow">B.Pierce's Types and Programming Languages</a>, also referred in the other answer). Programs that pass the type checking is a subset of what would be valid programs. For instance, the method <pre><code>int answer() { if(true) { return 42; } else { return "wrong"; } } </code></pre> would actually behave well at run-time. The else branch is never executed, and the answer always return 42. The static type system is a conservative analysis that will reject this program, because it can not prove the absence of a type error, that is, that "wrong" is never returned. Of course, you could improve the type system to actually detect that the else branch never happens. You want to improve the type system to reject as few program as possible. This is why type system have been enriched over the years to support more and more refinement (e.g. generic, etc.) The point of a type system is to prove the absence of type errors. In practice, they support operations like downcasting that inherently imply run-time type checks, and might lead to type errors. Again, the goal is to make the type system as flexible as possible, so that we don't need to resort to these operations that weaken type safety (e.g. generic). You can read chapter 1 of the aforementionned book for a really nice introduction. For the rest, I will refer you to <a href="http://blogs.perl.org/users/ovid/2010/08/what-to-know-before-debating-type-systems.html" rel="nofollow">What To Know Before Debating Type Systems</a>, which is awesome blog post about the basic concepts. <blockquote> Is there anything else I should know about type systems? </blockquote> Oh, yes! :) Happy immersion in the world of type systems!
Tags
Title
singulars
PostAcceptedAnswerId
1. This table or related slice is empty.
PostParentId
1. POBasic Concepts of Language Type Systems
 singulars
 PostTypePostTypeId
 PTQuestion
PostTypePostTypeId
1. PTAnswer
UserLastEditorUserId
1. This table or related slice is empty.
UserOwnerUserId
1. USewernli
plurals
PostLinksPostIdRelatedPostId
1. This table or related slice is empty.
PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. This table or related slice is empty.
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
 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.