StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
primarykey
Id
8572333
data
AcceptedAnswerId
0
AnswerCount
0
ClosedDate
CommentCount
0
CommunityOwnedDate
CreationDate
2011-12-20T07:57:10.793
FavoriteCount
0
LastActivityDate
2011-12-20T07:57:10.793
LastEditDate
LastEditorUserId
0
OwnerUserId
431620
ParentId
8569014
PostTypeId
2
Score
0
ViewCount
0
LastEditorDisplayName
text
Body
The statement <code>Fastest Way</code> to <code>return more than 5000 rows</code> depends on the problem in question. What is the database structure ? What do we want ? what is the record structure ? After those, then, it boils down to how you write your read functions. If we are sure about the primary key, then we use <code>mnesia:read/1 or mnesia:read/2</code> if not, its better and more beautiful to use <a href="http://www.erlang.org/doc/man/qlc.html" rel="nofollow">Query List comprehensions</a>. Its more flexible to search nested records and with complex conditional queries. see usage below: <pre> -include_lib("stdlib/include/qlc.hrl"). -record(bigdata, {mykey,some1,some2}). %% query list comprehenshions select(Q)-> %% to prevent against nested transactions %% to ensure it also works whether table %% is fragmented or not, we will use %% mnesia:activity/4 case mnesia:is_transaction() of false -> F = fun(QH)-> qlc:e(QH) end, mnesia:activity(transaction,F,[Q],mnesia_frag); true -> qlc:e(Q) end. %% to read by a given field or even several %% you use a list comprehension and pass the guards %% to filter those records accordingly read_by_field(some2,Value)-> QueryHandle = qlc:q([X || X <- mnesia:table(bigdata), X#bigdata.some2 == Value]), select(QueryHandle). %% selecting by several conditions read_by_several()-> %% you can pass as many guard expressions QueryHandle = qlc:q([X || X <- mnesia:table(bigdata), X#bigdata.some2 =< 300, X#bigdata.some1 > 50 ]), select(QueryHandle). %% Its possible to pass a 'fun' which will do the %% record selection in the query list comprehension auto_reader(ValidatorFun)-> QueryHandle = qlc:q([X || X <- mnesia:table(bigdata), ValidatorFun(X) == true]), select(QueryHandle). read_using_auto()-> F = fun({bigdata,SomeKey,_,Some2}) -> true; (_) -> false end, auto_reader(F). </pre> So i think if you want fastest way, we need more clarification and problem detail. Speed depends on many factors my dear ! 
Tags
Title
singulars
PostAcceptedAnswerId
1. This table or related slice is empty.
PostParentId
1. POGetting lots of data from Mnesia - fastest way
 singulars
 PostTypePostTypeId
 PTQuestion
PostTypePostTypeId
1. PTAnswer
UserLastEditorUserId
1. This table or related slice is empty.
UserOwnerUserId
1. USMuzaaya Joshua
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. This table or related slice is empty.
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.