StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
primarykey
Id
20020145
data
AcceptedAnswerId
0
AnswerCount
0
ClosedDate
CommentCount
0
CommunityOwnedDate
CreationDate
2013-11-16T15:27:11.007
FavoriteCount
0
LastActivityDate
2013-11-16T17:23:48
LastEditDate
2017-05-23T12:12:41.773
LastEditorUserId
-1
OwnerUserId
23771
ParentId
20019799
PostTypeId
2
Score
1
ViewCount
0
LastEditorDisplayName
text
Body
For that I use <a href="https://stackoverflow.com/questions/4445656/what-is-differential-execution">differential execution</a>. (BTW, the word "slave" is uncomfortable for some people, with reason.) For each remote site, there is a sequential file at the primary site representing what exists on the remote site. There is a procedure at the primary site that walks through the primary collection, and as it walks it reads the corresponding file, detecting differences between what currently exists on the remote site and what should exist. Those differences produce deltas, which are transmitted to the remote site. At the same time, the procedure writes a new file representing what will exist at the remote site after the deltas are processed. The advantage of this is it does not depend on detecting change events in the primary collection, because often those change events are unreliable or can be self-cancelling or made irrelevant by other changes, so you cut way down on needless transmissions to the remote site. In the case that the collections are simple lists of things, this boils down to having local copies of the remote collections and running a <code>diff</code> algorithm to get the delta. Here are a couple such algorithms: If the collections can be sorted (like your A,B,C example), just run a merge loop: <pre><code>while(ix<nx && iy<ny){ if (X[ix] < Y[iy]){ // X[ix] was inserted in X ix++; } else if (Y[iy] < X[ix]){ // Y[iy] was deleted from X iy++; } else { // the two elements are equal. skip them both; ix++; iy++; } } while(ix<nx){ // X[ix] was inserted in X ix++; } while(iy<ny>){ // Y[iy] was deleted from X iy++; } </code></pre> If the collections cannot be sorted (note relationship to <a href="https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CC4QFjAA&url=http://en.wikipedia.org/wiki/Levenshtein_distance&ei=p5-HUv6mAuzj4APMi4CADw&usg=AFQjCNHIZDhIk5K5Ml7K8baQz3u_o_-1NQ&sig2=TJ4oo15ivz5PWpbtGo_vww&bvm=bv.56643336,d.dmg" rel="nofollow noreferrer">Levenshtein distance</a>), <pre><code>Until we have read through both collections X and Y, See if the current items are equal else see if a single item was inserted in X else see if a single item was deleted from X else see if 2 items were inserted in X else see if a single item was replaced in X else see if 2 items were deleted from X else see if 3 items were inserted in X else see if 2 items in X replaced 1 items in Y else see if 1 items in X replaced 2 items in Y else see if 3 items were deleted from X etc. etc. up to some limit </code></pre> Performance is generally not an issue, because the procedure does not have to be run at high frequency. There's a <a href="https://www.youtube.com/watch?v=ibPR17IZZUM" rel="nofollow noreferrer">crude video demonstrating this concept</a>, and <a href="http://sourceforge.net/projects/dyndlgdemo/" rel="nofollow noreferrer">source code where it is used for dynamically changing user interfaces</a>.
Tags
Title
singulars
PostAcceptedAnswerId
1. This table or related slice is empty.
PostParentId
1. POEfficient data structure and strategy for synchronizing several item collections
 singulars
 PostTypePostTypeId
 PTQuestion
PostTypePostTypeId
1. PTAnswer
UserLastEditorUserId
1. USCommunity
UserOwnerUserId
1. USMike Dunlavey
plurals
PostLinksPostIdRelatedPostId
1. This table or related slice is empty.
PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. POEfficient data structure and strategy for synchronizing several item collections
 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
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.