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  • MySQL: Question about SELECT WHERE AND/OR

    - by Andrew
    I'm trying to write a query that returns the same result from three different events, but I think I am doing it wrong. I can run my query against one event ID and it works. How can I select all three? Here's what I have so far: SELECT * FROM `Registrations` WHERE `Role` = "Attendee" AND `RegistrationStatus_ID` = "1" AND `DigSignature` IS NULL AND `Event_ID` = "147" OR `Event_ID` = "155" OR `Event_ID` = "160"

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  • Table for each region in MySQL

    - by King Wu
    There are four regions with more than one million records total. Should I create a table with a region column or a table for each region and combine them to get the top ranks? If I combine all four regions, none of my columns will be unique so I will need to also add an id column for my primary key. Otherwise, name, accountId & characterId would be candidate keys or should I just add an id column anyways. Table: ---------------------------------------------------------------- | name | accountId | iconId | level | characterId | updateDate | ----------------------------------------------------------------

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  • Stop invalid data in a attribute with foreign key constraint using triggers?

    - by Eternal Learner
    How to specify a trigger which checks if the data inserted into a tables foreign key attribute, actually exists in the references table. If it exist no action should be performed , else the trigger should delete the inserted tuple. Eg: Consider have 2 tables R(A int Primary Key) and S(B int Primary Key , A int Foreign Key References R(A) ) . I have written a trigger like this : Create Trigger DelS BEFORE INSERT ON S FOR EACH ROW BEGIN Delete FROM S where New.A <> ( Select * from R;) ); End; I am sure I am making a mistake while specifying the inner sub query within the Begin and end Blocks of the trigger. My question is how do I make such a trigger ?

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  • Can MySQL reasonably perform queries on billions of rows?

    - by haxney
    I am planning on storing scans from a mass spectrometer in a MySQL database and would like to know whether storing and analyzing this amount of data is remotely feasible. I know performance varies wildly depending on the environment, but I'm looking for the rough order of magnitude: will queries take 5 days or 5 milliseconds? Input format Each input file contains a single run of the spectrometer; each run is comprised of a set of scans, and each scan has an ordered array of datapoints. There is a bit of metadata, but the majority of the file is comprised of arrays 32- or 64-bit ints or floats. Host system |----------------+-------------------------------| | OS | Windows 2008 64-bit | | MySQL version | 5.5.24 (x86_64) | | CPU | 2x Xeon E5420 (8 cores total) | | RAM | 8GB | | SSD filesystem | 500 GiB | | HDD RAID | 12 TiB | |----------------+-------------------------------| There are some other services running on the server using negligible processor time. File statistics |------------------+--------------| | number of files | ~16,000 | | total size | 1.3 TiB | | min size | 0 bytes | | max size | 12 GiB | | mean | 800 MiB | | median | 500 MiB | | total datapoints | ~200 billion | |------------------+--------------| The total number of datapoints is a very rough estimate. Proposed schema I'm planning on doing things "right" (i.e. normalizing the data like crazy) and so would have a runs table, a spectra table with a foreign key to runs, and a datapoints table with a foreign key to spectra. The 200 Billion datapoint question I am going to be analyzing across multiple spectra and possibly even multiple runs, resulting in queries which could touch millions of rows. Assuming I index everything properly (which is a topic for another question) and am not trying to shuffle hundreds of MiB across the network, is it remotely plausible for MySQL to handle this? UPDATE: additional info The scan data will be coming from files in the XML-based mzML format. The meat of this format is in the <binaryDataArrayList> elements where the data is stored. Each scan produces = 2 <binaryDataArray> elements which, taken together, form a 2-dimensional (or more) array of the form [[123.456, 234.567, ...], ...]. These data are write-once, so update performance and transaction safety are not concerns. My naïve plan for a database schema is: runs table | column name | type | |-------------+-------------| | id | PRIMARY KEY | | start_time | TIMESTAMP | | name | VARCHAR | |-------------+-------------| spectra table | column name | type | |----------------+-------------| | id | PRIMARY KEY | | name | VARCHAR | | index | INT | | spectrum_type | INT | | representation | INT | | run_id | FOREIGN KEY | |----------------+-------------| datapoints table | column name | type | |-------------+-------------| | id | PRIMARY KEY | | spectrum_id | FOREIGN KEY | | mz | DOUBLE | | num_counts | DOUBLE | | index | INT | |-------------+-------------| Is this reasonable?

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  • Change Label Control Property Based on Data from SqlDataSource Inside a Repeater

    - by Furqan Muhammad Khan
    I am using a repeater control to populate data from SqlDataSource into my custom designed display-box. <asp:Repeater ID="Repeater1" runat="server" DataSourceID="SqlDataSource1" OnDataBinding="Repeater_ItemDataBound"> <HeaderTemplate> </HeaderTemplate> <ItemTemplate> <div class="bubble-content"> <div style="float: left;"> <h2 class="bubble-content-title"><%# Eval("CommentTitle") %></h2> </div> <div style="text-align: right;"> <asp:Label ID="lbl_category" runat="server" Text=""><%# Eval("CommentType") %> </asp:Label> </div> <div style="float: left;"> <p><%# Eval("CommentContent") %></p> </div> </div> </ItemTemplate> <FooterTemplate> </FooterTemplate> </asp:Repeater> <asp:SqlDataSource ID="mySqlDataSource" runat="server" ConnectionString="<%$ ConnectionStrings:myConnectionString %>" SelectCommand="SELECT [CommentTitle],[CommentType],[CommentContent] FROM [Comments] WHERE ([PostId] = @PostId)"> <SelectParameters> <asp:QueryStringParameter Name="PostId" QueryStringField="id" Type="String" /> </SelectParameters> </asp:SqlDataSource> Now, there can be three types of "CommentTypes" in the database. I want to change the CssClass property of "lbl_category" based on the value of [CommentType]. I tried doing this: <asp:Label ID="lbl_category" runat="server" CssClass="<%# Eval("CommentType") %>" Text=""><%# Eval("CommentType") %></asp:Label> But this gives an error: "The server control is not well formed" and haven't been able to find a way to achieve this in the code behind. Can someone please help?

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  • How to store MySQL query results in another Table?

    - by Taz
    How to store results from following query into another table. Considering there is an appropriate table already created. SELECT labels.label,shortabstracts.ShortAbstract,images.LinkToImage,types.Type FROM ner.images,ner.labels,ner.shortabstracts,ner.types WHERE labels.Resource=images.Resource AND labels.Resource=shortabstracts.Resource AND labels.Resource=types.Resource;

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  • Select 2 Rows from Table when COUNT of another table

    - by Marcus
    Here is the code that I currently have: SELECT `A`.* FROM `A` LEFT JOIN `B` ON `A`.`A_id` = `B`.`value_1` WHERE `B`.`value_2` IS NULL AND `B`.`userid` IS NULL ORDER BY RAND() LIMIT 2 What it currently is supposed to do is select 2 rows from A when the 2 rows A_id being selected are not in value_1 or value_2 in B. And the rows in B are specific to individual users with userid. What I need to do is make it also so that also checks if there are already N rows in B matching a A_id (either in value_1, or value_2) and userid, and if there are more than N rows, it doesn't select the A row.

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  • MySQL Query, how to group and count in one row ?

    - by Akarun
    Hi All, To simplify, I have tree tables: products, products-vs-orders, orders products fields : 'ProductID', 'Name', 'isGratis', ... products-vs-orders fields : 'ProductID', 'OrderID' orders fields : 'OrderID', 'Title', ... Actually, I have a query like this: SELECT orders.OrderID, orders.Title, COUNT(`products`.`isGratis`) AS "Quantity", `products`.`isGratis` FROM `orders`, `products-vs-orders`, `products` WHERE `orders`.`OrderID` = `products-vs-orders`.`OrderID` AND `products-vs-orders`.`ProductID` = `products`.`ProductID` GROUP BY `products`.`PackID`, `products`.`isGratis` This query works and return this surch of result: OrderID, Title, Quantity, isGratis 1 My Order 20 0 1 My Order 3 1 2 An other 8 0 2 An other 1 1 How can I retrieve the count of products 'gratis' and 'paid' in to separate cols ? OrderID, Title, Qt Paid, Qt Gratis 1 My Order 20 3 2 An other 8 1 Thanks for your help

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  • How to use database to generate multiple folder content page?

    - by VenomVipes
    Scenario :I am trying to build a Mobile Entertainment Portal. It will enable users to download Music & Movies to their Cell Phones... Problem Exp : Suppose I upload 100 folders of Songs, each folder is for one Album. I want a way to generate a page with all the folders name (Album Name) in it. If user click on the page, they should be taken to a page where they get list of all songs in the album. Clicking on any song name will let them download it. Can it be done anyway or will I have to manually design each of the 3 pages for each album. If I do that, its time consuming and also will be difficult to change anything like footer, header...

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  • Will MySql caching cause performance problems?

    - by Camran
    I am about to upload my website onto a VPS. It is a classifieds website, where all data is stored in MySql and Solr. I wonder if when using MySql:s cache, the server will slow down? Ie, if somebody makes a search for the first time, and MySql is to cache the query, will the caching make the server slower than if it would not cache anything? After the caching is done I know things will improve in terms of performance... But I would like to know if I should even use the cache or not, what do you think? Thanks

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  • How to do this query?

    - by Damiano
    Hello everybody! I have a mysql table with these columns: ID (auto-increment) ID_BOOK (int) PRICE (double) DATA (date) I know two ID_BOOK values, example, 1 and 2. QUERY: I have to extract all the PRICE (of the ID_BOOK=1 and ID_BOOK=2) where DATA is the same! Table example: 1 1 10.00 2010-05-16 2 1 11.00 2010-05-15 3 1 12.00 2010-05-14 4 2 18.00 2010-05-16 5 2 11.50 2010-05-15 Result example: 1 1 10.00 2010-05-16 4 2 18.00 2010-05-16 2 1 11.00 2010-05-15 5 2 11.50 2010-05-15 ID_BOOK=2 hasn't 2010-05-14 so i jump it. Thank you so much!

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  • slow record deletion with large ntext values

    - by asking
    I'm having trouble deleting some records via a stored procedure from a table in SQLServer 2008R2 that has ntext columns. The stored proc is timing out and running the query directly takes a very long time. The initial query was a straight "delete from y where x = z" and I've also tried running it in batches of 1000 with transactions but it is still slow and timing out in a stored proc. The majority of the records in the table will not be deleted each time (it's not just a once-off query but will be run other times). The ntext columns are not used in the where clause and I can't change the column types. Any suggestions on the quickest way to delete records with large ntext values? Thanks

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  • CakePHP repeats same queries

    - by Rytis
    I have a model structure: Category hasMany Product hasMany Stockitem belongsTo Warehouse, Manufacturer. I fetch data with this code, using containable to be able to filter deeper in the associated models: $this->Category->find('all', array( 'conditions' => array('Category.id' => $category_id), 'contain' => array( 'Product' => array( 'Stockitem' => array( 'conditions' => array('Stockitem.warehouse_id' => $warehouse_id), 'Warehouse', 'Manufacturer', ) ) ), ) ); Data structure is returned just fine, however, I get multiple repeating queries like, sometimes hundreds of such queries in a row, based on dataset. SELECT `Warehouse`.`id`, `Warehouse`.`title` FROM `beta_warehouses` AS `Warehouse` WHERE `Warehouse`.`id` = 2 Basically, when building data structure Cake is fetching data from mysql over and over again, for each row. We have datasets of several thousand rows, and I have a feeling that it's going to impact performance. Is it possible to make it cache results and not repeat same queries?

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  • Avoiding repeated subqueries when 'WITH' is unavailable

    - by EloquentGeek
    MySQL v5.0.58. Tables, with foreign key constraints etc and other non-relevant details omitted for brevity: CREATE TABLE `fixture` ( `id` int(11) NOT NULL auto_increment, `competition_id` int(11) NOT NULL, `name` varchar(50) NOT NULL, `scheduled` datetime default NULL, `played` datetime default NULL, PRIMARY KEY (`id`) ); CREATE TABLE `result` ( `id` int(11) NOT NULL auto_increment, `fixture_id` int(11) NOT NULL, `team_id` int(11) NOT NULL, `score` int(11) NOT NULL, `place` int(11) NOT NULL, PRIMARY KEY (`id`) ); CREATE TABLE `team` ( `id` int(11) NOT NULL auto_increment, `name` varchar(50) NOT NULL, PRIMARY KEY (`id`) ); Where: A draw will set result.place to 0 result.place will otherwise contain an integer representing first place, second place, and so on The task is to return a string describing the most recently played result in a given competition for a given team. The format should be "def Team X,Team Y" if the given team was victorious, "lost to Team X" if the given team lost, and "drew with Team X" if there was a draw. And yes, in theory there could be more than two teams per fixture (though 1 v 1 will be the most common case). This works, but feels really inefficient: SELECT CONCAT( (SELECT CASE `result`.`place` WHEN 0 THEN "drew with" WHEN 1 THEN "def" ELSE "lost to" END FROM `result` WHERE `result`.`fixture_id` = (SELECT `fixture`.`id` FROM `fixture` LEFT JOIN `result` ON `result`.`fixture_id` = `fixture`.`id` WHERE `fixture`.`competition_id` = 2 AND `result`.`team_id` = 1 ORDER BY `fixture`.`played` DESC LIMIT 1) AND `result`.`team_id` = 1), ' ', (SELECT GROUP_CONCAT(`team`.`name`) FROM `fixture` LEFT JOIN `result` ON `result`.`fixture_id` = `fixture`.`id` LEFT JOIN `team` ON `result`.`team_id` = `team`.`id` WHERE `fixture`.`id` = (SELECT `fixture`.`id` FROM `fixture` LEFT JOIN `result` ON `result`.`fixture_id` = `fixture`.`id` WHERE `fixture`.`competition_id` = 2 AND `result`.`team_id` = 1 ORDER BY `fixture`.`played` DESC LIMIT 1) AND `team`.`id` != 1) ) Have I missed something really obvious, or should I simply not try to do this in one query? Or does the current difficulty reflect a poor table design?

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  • Can I have a CASE statement within a WHILE loop?

    - by John
    This is what I'm doing: while (@counter < 3 and @newBalance >0) begin CASE when @counter = 1 then ( @monFee1 = @monthlyFee, @newBalance = @newBalance-@fee) when @counter = 2 then ( @monFee2 = @monthlyFee, @newBalance = @newBalance-@fee) END @counter = @counter +1 end I get this error: Incorrect syntax near the keyword 'CASE'. No idea why. Please help!

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  • Losing scope for DataContex using LINQToSQL intermediately

    - by greektreat
    I am having a weird Situation with my DataConext. All My code is in C# I have a DLL project for my data access layer and business Layer which and Winforms project for my UI layer. My Data access Layer's Namespace is xxx.Data this is where have my xxx.dbml I also have xxx.Data.BusinessObjects name space of course for my business object in that project In my UI Layer I have these namespaces xxxApp(for Forms), xxxApp.Controls (For Controls) I have lost scope of the DataContext, it was accessible now when I do a Rebuild Solution I sometimes get compile errors saying for example: Error 34 'xxx.Data.xxxDataContext' does not contain a definition for 'SubmitChanges' and no extension method 'SubmitChanges' accepting a first argument of type 'xxx.Data.xxxDataContext' could be found (are you missing a using directive or an assembly reference?) Also intelisense doesn't recognize the methods and table classes from my xxxDataContext anymore I can access all object fine when I am in the DLL project but now in the Winforms project this is very strange. If anyone can help me out I would be extremely grateful!

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  • (NOT) NULL for NVARCHAR columns

    - by Anders Abel
    Allowing NULL values on a column is normally done to allow the absense of a value to be represented. When using NVARCHAR there is aldready a possibility to have an empty string, without setting the column to NULL. In most cases I cannot see a semantical difference between an NVARCHAR with an empty string and a NULL value for such a column. Setting the column as NOT NULL saves me from having to deal with the possibility of NULL values in the code and it feels better to not have to different representations of "no value" (NULL or an empty string). Will I run into any other problems by setting my NVARCHAR columns to NOT NULL. Performance? Storage size? Anything I've overlooked on the usage of the values in the client code?

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  • MySQL: Limit output according to associated ID

    - by Jess
    So here's my situation. I have a books table and authors table. An author can have many books... In my authors page view, the user (logged in) can click an author in a tabled row and be directed to a page displaying the author's books (collected like this URI format: viewauthorbooks.php?author_id=23), very straight forward... However, in my query, I need to display the books for the author only, and not all books stored in the books table (as i currently have!) As I am a complete novice, I used the most simple query of: SELECT * FROM tasks_tb This returns the books for me, but returns every single value (book) in the database, and not ones associated with the selected author. And when I click a different author the same books are displayed for them...I think everyone gets what I'm trying to achieve, I just don't know how to perform the query. I'm guessing that I need to start using more advanced query clauses like INNER JOIN etc. Anyone care to help me out :)

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