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  • What is the most "database independent" way of creating a variable length text field in a database

    - by Thibaut Colar
    I want to create a text field in the database, with no specific size (it will store text of length unknown in some case) - the particular text are serialized simple object (~ JSON) What is the most database independent way to do this : - a varchar with no size specified (don't think all db support this) - a 'text' field, this seems to be common, but I don't believe it's a standard - a blob or other object of that kind ? - a varchar of a a very large size (that's inefficient and wastes disk space probably) - Other ? I'm using JDBC, but I'd like to use something that is supported in most DB (oracle, mysql, postgresql, derby, HSQL, H2 etc...) Thanks.

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  • MySQL COUNT() total posts within a specific criteria?

    - by newbtophp
    Hey, I've been losing my hair trying to figure out what I'm doing wrong, let me explain abit about my MySQL structure (so you get a better understanding) before I go straight to the question. I have a simple PHP forum and I have a column in both tables (for posts and topics) named 'deleted' if it equals 0 that means its displayed (considered not deleted/exists) or if it equals 1 it hidden (considered deleted/doesn't exist) - bool/lean. Now, the 'specific criteria' I'm on about...I'm wanting to get a total post count within a specific forum using its id (forum_id), ensuring it only counts posts which are not deleted (deleted = 0) and their parent topics are not deleted either (deleted = 0). The column/table names are self explanatory (see my efforts below for them - if needed). I've tried the following (using a 'simple' JOIN): SELECT COUNT(t1.post_id) FROM forum_posts AS t1, forum_topics AS t2 WHERE t1.forum_id = '{$forum_id}' AND t1.deleted = 0 AND t1.topic_id = t2.topic_id AND t2.deleted = 0 LIMIT 1 I've also tried this (using a Subquery): SELECT COUNT(t1.post_id) FROM forum_posts AS t1 WHERE t1.forum_id = '{$forum_id}' AND t1.deleted = 0 AND (SELECT deleted FROM forum_topics WHERE topic_id = t1.topic_id) = 0 LIMIT 1 But both don't comply with the specific criteria. Appreciate all help! :)

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  • Replace always replacing null values

    - by Mike
    Why does left(FIELD, replace(nullif(charindex('-', FIELD), 0), null, len(FIELD))) always return null? The idea behind the query is that if charindex() returns 0, then convert the results into null, then convert the null into the length of the field. So if '-' does not exist, show the whole string. For some reason it makes every row equal null. Thank you.

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  • Database design -- does it respect 3rd NF?

    - by Flavius
    Hi I have the following relations (tables) in a relational model Person person_id, first_name, last_name, address Student person_id, matr_nr Teacher person_id, salary Lecture lecture_id, lect_name, lect_description Attendees lecture_id, person_id, date I'm wondering about the functional dependencies of Student and Teacher. Do these tables respect the 3rd normal form? Which should be the primary keys of these tables?

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  • How do I do a table join on two fields in my second table?

    - by Cannonade
    I have two tables: Messages - Amongst other things, has a to_id and a from_id field. People - Has a corresponding person_id I am trying to figure out how to do the following in a single linq query: Give me all messages that have been sent to and from person x (idself). I had a couple of cracks at this. Not quite right MsgPeople = (from p in db.people join m in db.messages on p.person_id equals m.from_id where (m.from_id == idself || m.to_id == idself) orderby p.name descending select p).Distinct(); This almost works, except I think it misses one case: "people who have never received a message, just sent one to me" How this works in my head So what I really need is something like: join m in db.messages on (p.people_id equals m.from_id or p.people_id equals m.to_id) Gets me a subset of the people I am after It seems you can't do that. I have tried a few other options, like doing two joins: MsgPeople = (from p in db.people join m in AllMessages on p.person_id equals m.from_id join m2 in AllMessages on p.person_id equals m2.to_id where (m2.from_id == idself || m.to_id == idself) orderby p.name descending select p).Distinct(); but this gives me a subset of the results I need, I guess something to do with the order the joins are resolved. My understanding of LINQ (and perhaps even database theory) is embarrassingly superficial and I look forward to having some light shed on my problem.

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  • “Function” calling inside store procedure

    - by idimba
    Hi, I have a big store procedure, that contains a lot of INSERTs. There're many INSERTS that almost identical - they're different by some parameter(s) (all INSERTs to the same table) Is there a way to create a function/method, to which I'll pass the above parameter(s) and the function/method will generate concrete INSERT's? Thanks

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  • Join using combined conditions on one join table

    - by Nathan Wienert
    I have join a table joining songs to genres. The table has a 'source' column that's used to identify where the genre was found. Genres are found from blogs, artists, tags, and posts. So, songs | song_genre | genres id | song_id, source, genre_id | id What I want to build is a song SELECT query that works something like this, given I already have a genre_id: IF exists song_genre with source='artist' AND a song_genre with source='blog' OR exists song_genre with source='artist' AND a song_genre with source='post' OR exists song_genre with source='tag' I'm was going to do it by doing a bunch of joins, but am sure I'm not doing it very well. Using Postgres 9.1.

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  • How do I execute a sql statement through a variable (dyname sql) that tries to do an insert into a variable table?

    - by Testifier
    If I do what I wanna do with a TEMPORARY TABLE, it works fine: DECLARE @CTRFR VARCHAR(MAX) SET @CTRFR = 'select blah blah blah' -- <-- very long select statement. this returns a 0 or some greater number. Please note! --> I NEED THIS NUMBER. IF EXISTS ( SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo][#CTRFRResult]') AND type IN ( N'U' ) ) DROP TABLE [dbo].[#CTRFRResult] CREATE TABLE #CTRFRResult ( CTRFRResult VARCHAR(MAX) ) SET @CTRFR = 'insert into #CTRFRResult ' + @CTRFR EXEC(@CTRFR) The above works fine. The problem is that several databases are using the same TEMP table. Therefore I need to use a VARIABLE table (instead of a temporary table). What I have below is not working because it says that the table must be declared. DECLARE @CTRFRResult TABLE ( CTRFRResult VARCHAR(MAX) ) SET @CTRFR = 'insert into @CTRFRResult ' + @CTRFR -- I think the issue is here. EXEC(@CTRFR) Setting @CTRFR to 'insert into...' is not working because I'm assuming the table name is out of scope. How would I go about mimicking the temporary table code using a variable table?

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  • Is there a better way to do updates in LinqToSQL?

    - by Vaccano
    I have a list (that comes to my middleware app from the client) that I need to put in my database. Some items in the list may already be in the db (just need an update). Others are new inserts. This turns out to be much harder than I thought I would be. Here is my code to do that. I am hoping there is a better way: public void InsertClients(List<Client> clients) { var comparer = new LambdaComparer<Client>((x, y) => x.Id == y.Id); // Get a listing of all the ones we will be updating var alreadyInDB = ctx.Clients .Where(client => clients.Contains(client, comparer)); // Update the changes for those already in the db foreach (Client clientDB in alreadyInDB) { var clientDBClosure = clientDB; Client clientParam = clients.Find(x => x.Id == clientDBClosure.Id); clientDB.ArrivalTime = clientParam.ArrivalTime; clientDB.ClientId = clientParam.ClientId; clientDB.ClientName = clientParam.ClientName; clientDB.ClientEventTime = clientParam.ClientEventTime; clientDB.EmployeeCount = clientParam.EmployeeCount; clientDB.ManagerId = clientParam.ManagerId; } // Get a list of all clients that are not in my the database. var notInDB = clients.Where(x => alreadyInDB.Contains(x, comparer) == false); ctx.Clients.InsertAllOnSubmit(notInDB); ctx.SubmitChanges(); } This seems like a lot of work to do a simple update. But maybe I am just spoiled. Anyway, if there is a easier way to do this please let me know. Note: If you are curious the code to the LambdaComparer is here: http://gist.github.com/335780#file_lambda_comparer.cs

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  • Changing newid() to newsequentialid() on an existing table

    - by cbp
    Hi, At the moment we have a number of tables that are using newid() on the primary key. This is causing large amounts of fragmentation. So I would like to change the column to use newsequentialid() instead. I imagine that the existing data will remain quite fragmented but the new data will be less fragmented. This would imply that I should perhaps wait some time before changing the PK index from non-clustered to clustered. My question is, does anyone have experience doing this? Is there anything I have overlooked that I should be careful of?

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  • How to get only one record for each duplicate rows of the id in oracle?

    - by Psychocryo
    suppose i have this table: group_id | image | image_id | ----------------------------- 23 blob 1 23 blob 2 23 blob 3 21 blob 4 21 blob 5 25 blob 6 25 blob 7 how to get results of only 1 of each group id? in this case,there may be multiple images for one group id, i just want one result of each group_id i tried distinct but i will only get group_id. max for image also would not work.

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  • it is possible to "group by" without losing the original rows?

    - by toPeerOrNotToPeer
    i have a query like this: ID | name | commentsCount 1 | mysql for dummies | 33 2 | mysql beginners guide | 22 SELECT ..., commentsCount // will return 33 for first row, 22 for second one FROM mycontents WHERE name LIKE "%mysql%" also i want to know the total of comments, of all rows: SELECT ..., SUM(commentsCount) AS commentsCountAggregate // should return 55 FROM mycontents WHERE name LIKE "%mysql%" but this one obviously returns a single row with the total. now i want to merge these two queries in one single only, because my actual query is very heavy to execute (it uses boolean full text search, substring offset search, and sadly lot more), then i don't want to execute it twice is there a way to get the total of comments without making the SELECT twice? !! custom functions are welcome !! also variable usage is welcome, i never used them...

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  • Creating temporary tables in MySQL Stored Procedure

    - by burntblark
    The following procedure gives me an error when I invoke it using the CALL statement: CREATE DEFINER=`user`@`localhost` PROCEDURE `emp_performance`(id VARCHAR(10)) BEGIN DROP TABLE IF EXISTS performance; CREATE TABLE performance AS SELECT time_in, time_out, day FROM attendance WHERE employee_id = id; END The error says "Unknown table 'performance' ". This is my first time actually using stored procedures and I got my sources from Google. I just cant figure out what I am doing wrong.

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  • How to output multiple rows from an SQL query using the mysqli object

    - by Jonathan
    Assuming that the mysqli object is already instantiatied (and connected) with the global variable $mysql, here is the code I am trying to work with. class Listing { private $mysql; function getListingInfo($l_id = "", $category = "", $subcategory = "", $username = "", $status = "active") { $condition = "`status` = '$status'"; if (!empty($l_id)) $condition .= "AND `L_ID` = '$l_id'"; if (!empty($category)) $condition .= "AND `category` = '$category'"; if (!empty($subcategory)) $condition .= "AND `subcategory` = '$subcategory'"; if (!empty($username)) $condition .= "AND `username` = '$username'"; $result = $this->mysql->query("SELECT * FROM listing WHERE $condition") or die('Error fetching values'); $this->listing = $result->fetch_array() or die('could not create object'); foreach ($this->listing as $key => $value) : $info[$key] = stripslashes(html_entity_decode($value)); endforeach; return $info; } } there are several hundred listings in the db and when I call $result-fetch_array() it places in an array the first row in the db. however when I try to call the object, I can't seem to access more than the first row. for instance: $listing_row = new Listing; while ($listing = $listing_row-getListingInfo()) { echo $listing[0]; } this outputs an infinite loop of the same row in the db. Why does it not advance to the next row? if I move the code: $this->listing = $result->fetch_array() or die('could not create object'); foreach ($this->listing as $key => $value) : $info[$key] = stripslashes(html_entity_decode($value)); endforeach; if I move this outside the class, it works exactly as expected outputting a row at a time while looping through the while statement. Is there a way to write this so that I can keep the fetch_array() call in the class and still loop through the records?

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  • What is your reporting tool of choice?

    - by jms
    Every project invariably needs some type of reporting functionality. From a foreach loop in your language of choice to a full blow BI platform. To get the job done what tools, widgets, platforms has the group used with success, frustration and failure?

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  • Voting Script, Possiblity of Simplifying Database Queries

    - by Sev
    I have a voting script which stores the post_id and the user_id in a table, to determine whether a particular user has already voted on a post and disallow them in the future. To do that, I am doing the following 3 queries. SELECT user_id, post_id from votes_table where postid=? AND user_id=? If that returns no rows, then: UPDATE post_table set votecount = votecount-1 where post_id = ? Then SELECT votecount from post where post_id=? To display the new votecount on the web page Any better way to do this? 3 queries are seriously slowing down the user's voting experience

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  • ASP.NET Template Selector/Builder - Dynamic CMS

    - by Ugene
    I am currently building my own CMS for various reasons that could take a long to explain... However i am looking for a dynamic solution to create templates for pages within the CMS and all areas must be editable via the administration area, maybe large text areas broken into multiple areas, text and image area on a page etc. Following on from the above i would like to create the following: Create a new page (selecting a pre-defined template like below) http://img525.imageshack.us/img525/9872/nestedpages.png and then upon editing the page it would have created as many text editors required for each editable region or a file upload control for an image area for example. i am thinking of using nested masterpages for the design elements, just unsure the best-practice way to achieve the above (db structure etc) I somehow hope this provides enough information but are happy to answer any questions you may have. Thanks

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  • Multiple LIKE, OR MySql Queries Match

    - by Codex73
    Search for: 'chemist' Problem: query which will match a string like 'onechemist' but not 'chemist'. SELECT id,name FROM `records` WHERE name LIKE '%". mysql_real_escape_string($q) ."%' This alternate try won't work: SELECT id,name FROM `records` WHERE name LIKE '%". mysql_real_escape_string($q) ."%' OR name LIKE '". mysql_real_escape_string($q) ."%' OR name LIKE '%". mysql_real_escape_string($q) ."' How could I compile the above into one single query that will match any field which has the string or optimize the query into a better expression?

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  • Where can I find documentation for Scala's delayed function calls?

    - by Geo
    I saw a delayed example in David Pollak's "Beginning Scala". I tried to adapt that, by trial and error. Here's what I have: def sayhello() = { println("hello") } def delaying(t: => Unit):Unit = { println("before call") t println("after call") } delaying(sayhello()) How would you delay a function/method that takes parameters? Why can't I use parantheses when I call t? Where can I find more documentation on delaying functions?

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  • Does UNIQ constraint mean also an index on that field(s)?

    - by Gremo
    As title, should i defined a separate index on email column (for searching purposes) or the index is "automatically" added along with UNIQ_EMAIL_USER constraint? CREATE TABLE IF NOT EXISTS `customer` ( `id` int(11) NOT NULL AUTO_INCREMENT, `user_id` int(11) NOT NULL, `first` varchar(255) NOT NULL, `last` varchar(255) NOT NULL, `slug` varchar(255) NOT NULL, `email` varchar(255) NOT NULL, `created_at` datetime NOT NULL, `updated_at` datetime NOT NULL, PRIMARY KEY (`id`), UNIQUE KEY `UNIQ_SLUG` (`slug`), UNIQUE KEY `UNIQ_EMAIL_USER` (`email`,`user_id`), KEY `IDX_USER` (`user_id`) ) ENGINE=InnoDB;

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  • Determining child count of path

    - by sqlnewbie
    I have a table whose 'path' column has values and I would like to update the table's 'child_count' column so that I get the following output. path | child_count --------+------------- | 5 /a | 3 /a/a | 0 /a/b | 1 /a/b/c | 0 /b | 0 My present solution - which is way too inefficient - uses a stored procedure as follows: CREATE FUNCTION child_count() RETURNS VOID AS $$ DECLARE parent VARCHAR; BEGIN FOR parent IN SELECT path FROM my_table LOOP DECLARE tokens VARCHAR[] := REGEXP_SPLIT_TO_ARRAY(parent, '/'); str VARCHAR := ''; BEGIN FOR i IN 2..ARRAY_LENGTH(tokens, 1) LOOP UPDATE my_table SET child_count = child_count + 1 WHERE path = str; str := str || '/' || tokens[i]; END LOOP; END; END LOOP; END; $$ LANGUAGE plpgsql; Anyone knows of a single UPDATE statement that does the same thing?

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