In have entities: Collection and Item. Each collection has many items. Both Collection and Item can be edited collaboratively by all users of the application. I have to provide a way to undo changes. Versioning Item records is straightforward, the difficult part is to version the relation between the Collection and Item. The allowed op...
I'm trying to model a site similar to StackOverflow. It has a set of users and questions, and user vote on questions. Each user can only have one vote on each question. What should the structure of my "VotesOnQuestions" table look like: Should I have an auto-generated "VoteID" column? How do I disallow, at the schema level, a user fro...
Related: http://stackoverflow.com/questions/492515/how-to-store-lightweight-formatting-textile-markdown-in-database I want to store comment formatting in some markup language in our DB. However, we want to allow multiple formatting languages (markdown, textile, restructuredText). It seems we should store a superset of their features, so...
I have a Wordpress site that uses two databases -- one section queries one database ("database_A"), and then Wordpress makes its connection to its own database ("database_B"). Everything it working well until I go to call this function: $pageposts = $wpdb->get_results($querystr, OBJECT); The Wordpress suddenly selects the wrong datab...
i have created a DB with 3 columns: aid, qid and message. aid is a foreign key which will be commond with another table. comments is a varchar which stores user comments its partially working. the problem is aid is not adding duplicate values. suppose i want to add comments related to specific aid. there are 18 aid's in all. and i wa...
Are there general ABAP-specific tips related to performance of big SELECT queries? In particular, is it possible to close once and for all the question of FOR ALL ENTRIES IN vs JOIN? ...
I am thinking about using transactions in 2-tier WPF (or windows forms) applications in following way: We can begin new transaction when we open new form for editing data, edit and persist changes transparently in this transaction. Then we can click "OK" button and commit transaction, or "Cancel" button and rollback it. If we want to op...
I'm trying to connect to Sybase database from the web server using UnixODBC. Sybase is installed on windows server while the web server is on Unix Server. In order to connect to Sybase I'm using UnixODBC which requires the file libdbodbc.so for Sybase I'm trying to locate this file but I'm unable to find it anywhere. Anyone can tell ...
I have three tables, tableA (id, A), tableB (id,B) and tableC (id,C). id is unique and primary key. Now I want to run a query on these three tables to find out sum of values of A,B and C for every id. (i.e. if id 1 is present in tableA but not in tableB then value B should be considered as 0 for id 1).example: tableA: id A 1 5 2 6 ...
I encountered an interesting SQL table (column names listed): From_TableName | From_Id | To_TableName | To_Id From what I understood, this table is used for all table relationships in the database. There's not a lot of data (more than 10000 lines in the previously mentioned table) in the database, so, I guess, performance was not that i...
Can we manage UDFs, and triggers in Derby database from our own Java Application ? By managing I mean : checking if it exists; adding; removing. ...
I want to change the permissions for all the tables in a SQL-Server database at once. Is there a way to do this? ...
We have a table that has a blob column along with other simple fields. Number of rows is about 6K, and sum of length of the blob column for all rows accounted for about 30MB. however when we ran a query to find the actual table space occupied, it was about 10GB(Database size itself is 11GB). We are wondering if, Would aborting transact...
Hi and thanks for your help, I am trying to select a radio button based on an ASP variable. This variable directly correlates to the value field of the radio button. Any ideas guys/gals? Thanks, Will ...
Hi, I was wondering what would be the best way to implement undirected graphs (and hence graph traversal) on Google App Engine. I'm currently storing edges in the database as a list, i.e. class Relation(db.Model): connect = db.ListProperty(str, required=True) but this is notoriously inefficient. I'm aware of the directed graph qu...
And here i am again! ;) Im developing (well, im still in planning phase) a web-app where i would give to other developer the possibility to write theyr own plugins/modules (in the way of CMS does, drupal, joomla, etc). My problem is that i have to force the developers to use the methods i wrote for interact with databases, for many rea...
I just stumbled upon Disqus today and am wondering why I would ever need to create my own Comment/Post model again :). Does Disqus store comments in their own database or do you have to store them too? How does this impact performance? Is Disqus worth it? ...
I have several SQL Server 2005 databases ranging from 20 – 600 tables in an application and no documentation. I am looking for a database diagramming tool that is smart enough to pick tables that seem to be related to one entity (e.g., tables related to Patient, tables related to Orders) or one functionality (e.g., Patient Management, Or...
I am working on a requirement to match people from different databases. One tricky problem is variance in names like Bob - Robert, Jim - James, Lizzy - Elizabeth etc across databases. Is there a lookup/translation available for this kind of a requirement. ...
Hi experts,, I have opened the database of drupal 7 and looked up in the tables node, node_revisions and node types and couldn't find where drupal stores the actual body of the node (content). any body have a clue? ...