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  • mysql database design: thread and reply of a reply?

    - by ajsie
    in my forum i have threads and replies. one thread has multiple replies. but then, a reply can be a reply of an reply (like google wave). because of that a reply has to have a column "reply_id" so it can point to the parent reply. but then, the "top-level" replies (the replies directly under the thread) will have no parent reply. so how can i fix this? how should the columns be in the reply table (and thread table). at the moment it looks like this: threads: id title body replies: id thread_id (all replies will belong to a thread) reply_id (here lies the problem. the top-level replies wont have a parent reply) body what could a smart design look like to enable reply a reply?

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  • Is there a work-around that allows missing data to equal NULL for LOAD DATA INFILE in MySQL?

    - by richardh
    I have a lot of large csv files with NULL values stored as ,, (i.e., no entry). After a lot of searching I found that this is a known "bug", although it may be a feature for some users. Is there a way that I can fix this on the fly without pre-processing? These data are all numeric, so a zero value is very different from NULL. Or if I have to do pre-processing, is there one that is most promising for dealing with tens of csv files of 100mb to 1gb? Thanks!

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  • ASP.NET MVC image upload store location (db vs filesystem)

    - by adrin
    I am writing web application using ASP.NET MVC + NHibernate + Postres stack. I wonder if images uploaded should be stored in database as binary blobs or on filesystem (and reference only in db). One advantage of db storage I can think of is easy backup/recovery of all data without reverting to filesystem copy tools. On the other hand I suspect that filesystem access may be faster (but is it especially when dealing with many concurrent requests?) What are your suggestions?

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  • Can someone recommend a good tutorial on MySQL indexes, specifically when used in an order by clause

    - by Philip Brocoum
    I could try to post and explain the exact query I'm trying to run, but I'm going by the old adage of, "give a man a fish and he'll eat for a day, teach a man to fish and he'll eat for the rest of his life." SQL optimization seems to be very query-specific, and even if you could solve this one particular query for me, I'm going to have to write many more queries in the future, and I'd like to be educated on how indexes work in general. Still, here's a quick description of my current problem. I have a query that joins three tables and runs in 0.2 seconds flat. Awesome. I add an "order by" clause and it runs in 4 minutes and 30 seconds. Sucky. I denormalize one table so there is one fewer join, add indexes everywhere, and now the query runs in... 20 minutes. What the hell? Finally, I don't use a join at all, but rather a subquery with "where id in (...) order by" and now it runs in 1.5 seconds. Pretty decent. What in God's name is going on? I feel like if I actually understood what indexes were doing I could write some really good SQL. Anybody know some good tutorials? Thanks!

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  • Implementing Tagging System with PHP and mySQL. Caching help!!!

    - by Hamid Sarfraz
    With reference to this post: http://stackoverflow.com/questions/2122546/how-to-implement-tag-counting I have implemented the suggested 3 table tagging system completely. To count the number of Articles per tag, i am using another column named tagArticleCount in the tag definition table. (other columns are tagId, tagText, tagUrl, tagArticleCount). If i implement realtime editing of this table, so that whenever user adds another tag to article or deletes an existing tag, the tag_definition_table is updated to update the counter of the added/removed tag. This will cost an extra query each time any modification is made. (at the same time, related link entry for tag and article is deleted from tagLinkTable). An alternative to this is not allowing any real time editing to the counter, instead use CRONs to update counter of each tag after a specified time period. Here comes the problem that i want to discuss. This can be seen as caching the article count in database. Can you please help me find a way to present the articles in a list when a tag is explored and when the article counter for that tag is not up to date. For example: 1. Counter shows 50 articles, but there are infact 55 entries in the tag link table (that links tags and articles). 2. Counter shows 50 articles, but there are infact 45 extries in the tag link table. How to handle these 2 scenerios given in example. I am going to use APC to keep cache of these counters. Consider it too in your solution. Also discuss performance in the realtime / CRONNED counter updates.

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  • New to CakePHP -> How To Add Columns To a MySQL Table?

    - by walden
    I had a website made for me a long time ago, and the programmer did it in CakePHP. I'm now editing his scripts. I added a couple columns to a table, and found that doing saveField() on the new column does not do anything. How do I make CakePHP recognize the new columns? I'd appreciate your help. I'm not too familiar with CakePHP, so please go easy on me =)

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  • How to configure DB connection in a Servlet based JPA application

    - by deamon
    By default DB connections of JPA applications are configured in the META-INF/persistence.xml, when the application is not deployed to a full Java EE application server. In my opinion it is not very elegant to place such environment specific configuration into a file that is inside a .war file. How could a DB connection of a Servlet based JPA application be configured more flexible (=outside of the .war file)?

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  • Does MySQL allow two primary keys on one table?

    - by Bharanikumar
    CREATE TABLE Orders -> ( -> ID SMALLINT UNSIGNED NOT NULL, -> ModelID SMALLINT UNSIGNED NOT NULL, -> Descrip VARCHAR(40), -> PRIMARY KEY (ID, ModelID) -> ); Basically, this appears to me to be creating two primary key on one table. Is that correct? I thought that we could create a number of unique keys in one table, but only one primary key. How is it that my system is allowing the creation of multiple primary keys? Please advise: what are the rules governing this?

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  • Best Practice for Exporting an App's Data to XML via PHP/MySQL?

    - by Alex Cook
    I have an a business app and I want to give my users the ability to export their data at anytime. I'm aware that I can write an XML file semi-manually by doing something like this: http://www.kirupa.com/web/mysql_xml_php.htm But, I thought I'd ask if this is the best practice? Or is there some framework I can use to do this more easily/quickly? Maybe there isn't - it won't be too hard to do it the above way. Also, less importantly - XML is the best format to export to, right? Thanks in advance.

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  • How to count how many items for distinct items in mysql?

    - by Vincent Duprez
    Imagine a have a table with a column named status: status ------ A A A B C C D D D How can I count how many rows have A, how many rows have B etc? this kind of output: A |B |C |D |E ------------------ 3 |1 |2 |3 |0 As for E = O , this will always be A,B,C,D and E Output should be one row (thus 1 query). When doing a distinct count (most returning answer on my searches, it does return how many different elements there are, 4 in this case...)

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  • Why is only 2 of my querys working? (PHP/Mysql)

    - by ggfan
    When I remove a posting, I want it to remove the posting itself, any comments related to it, and like/dislike of the comments, and favorites that people added. So there are 4 queries that do this, but somehow only 2 of the 4 are working. When I switch say query 2 for query 3, then query 2 works and query 3 doesn't... The table names are correct and it is getting the data via $_GET. // Grab the data from the GET $posting_id = $_GET['posting_id']; // Delete the posting from the database $query = "DELETE FROM posting WHERE posting_id=$posting_id LIMIT 1"; mysqli_query($dbc, $query) or die(mysql_error()); // Delete the comments $query2 = "DELETE FROM comments WHERE posting_id=$posting_id "; mysqli_query($dbc, $query2) or die(mysql_error()); // Delete the like/dislike $query3 = "DELETE FROM comment_likedislike WHERE posting_id=$posting_id "; mysqli_query($dbc, $query3) or die(mysql_error()); // Delete the favorites $query4 = "DELETE FROM favorite WHERE posting_id=$posting_id "; mysqli_query($dbc, $query4) or die(mysql_error());

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  • MySQL/PHP: How to insert logged in user id into another table that is gathering data from a form tha

    - by Lisa
    For the first time I am needing to join information from two tables and am quite nervous about doing it without any advice first. Basically, I am building a secure site that is accessed by authorised users. I have my login table with user_id, username, password Once the user is on the site, they have the option of inputting data into another table called input. At the moment this table only captures the information that is entered, not the user_id or username of the inputter. I would like the form to be able to input the user_id and/or username from the login table into the input table. Please could somebody talk me through this process? I am sure that once this is amended, I will then be able to use the table to only allow the logged in user to access the information that he or she have inputted, is that correct? Many thanks

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  • Create DB in Sql Server based on Visio Data Model

    - by Yaakov Ellis
    I have created a database model in Visio Professional (2003). I know that the Enterprise version has the ability to create a DB in Sql Server based on the data in Visio. I do not have the option to install Enterprise. Aside from going through the entire thing one table and relationship at a time and creating the whole database from scratch, by hand, can anyone recommend any tool/utility/method for converting the visio database model into a Sql Script that can be used to create a new DB in Sql Server?

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  • PHP mysql - ...AND column='anything'... ?

    - by Nike
    Is there any way to check if a column is "anything"? The reason is that i have a searchfunction that get's an ID from the URL, and then it passes it through the sql algorithm and shows the result. But if that URL "function" (?) isn't filled in, it just searches for: ...AND column=''... and that doesn't return any results at all. I've tried using a "%", but that doesn't do anything. Any ideas?

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  • Which of the two ways should I use to insert tags into mysql?

    - by ggfan
    For each ad, I allow users to choose up to 5 tags. Right now, in my database, I have it like... Posting_id TagID 5 1 5 2 5 3 6 5 6 1 But i was thinking if I should make it like... Posting_id TagID 5 1 2 3 6 5 1 Then first option is much easier to insert and retrieve data. But if I have 100 posts with 3 tags each, that's 300 rows...so ALOT more rows The second option requires using explode() impode(), etc but it is much cleaner. Which option should I do and why? thanks!

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  • Are there drawbacks to altering MySQL table data types?

    - by Tower
    Hi, I'm wondering that how much worried I should be about data types. I can easily jump from TINYINT to SMALLINT and from SMALLINT to INT, but are there any drawbacks to this? Obviously situations like from text to int will have consequences, but I'm talking about situations like INT-BIGINT, TINYTEXT-TEXT, etc.

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  • Drupal 6: using too many Views module causing site to go down cos of too many mysql connection.

    - by artmania
    Hi friends, I have HostGator Baby Shared Plan . I develop Drupal site on. everything was fine at the beginning, then by the time i go further with development, site started ti work really slow. now it is not working at all. giving my sql errors like TOO many connections, etc... I created so many blocks, pages with View. so it makes my site to so much depend on database. should not I do that? can it be the reason of my site's no working now. appreciate helps!!!!

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  • SELECT SQL Variable - should i avoid using this syntax and always use SET?

    - by Sholom
    Hi All, This may look like a duplicate to here, but it's not. I am trying to get a best practice, not a technical answer (which i already (think) i know). New to SQL Server and trying to form good habits. I found a great explanation of the functional differences between SET @var = and SELECT @var = here: http://vyaskn.tripod.com/differences_between_set_and_select.htm To summarize what each has that the other hasn't (see source for examples): SET: ANSI and portable, recommended by Microsoft. SET @var = (SELECT column_name FROM table_name) fails when the select returns more then one value, eliminating the possibility of unpredictable results. SET @var = (SELECT column_name FROM table_name) will set @var to NULL if that's what SELECT column_name FROM table_name returned, thus never leaving @var at it's prior value. SELECT: Multiple variables can be set in one statement Can return multiple system variables set by the prior DML statement SELECT @var = column_name FROM table_name would set @var to (according to my testing) the last value returned by the select. This could be a feature or a bug. Behavior can be changed with SELECT @j = (SELECT column_name FROM table_name) syntax. Speed. Setting multiple variables with a single SELECT statement as opposed to multiple SET/SELECT statements is much quicker. He has a sample test to prove his point. If you could design a test to prove the otherwise, bring it on! So, what do i do? (Almost) always use SET @var =, using SELECT @var = is messy coding and not standard. OR Use SELECT @var = freely, it could accomplish more for me, unless the code is likely to be ported to another environment. Thanks

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