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  • How do I make my MySQL query with joins more concise?

    - by John Hoffman
    I have a huge MySQL query that depends on JOINs. SELECT m.id, l.name as location, CONCAT(u.firstName, " ", u.lastName) AS matchee, u.email AS mEmail, u.description AS description, m.time AS meetingTime FROM matches AS m LEFT JOIN locations AS l ON locationID=l.id LEFT JOIN users AS u ON (u.id=m.user1ID) WHERE m.user2ID=2 UNION SELECT m.id, l.name as location, CONCAT(u.firstName, " ", u.lastName) AS matchee, u.email AS mEmail, u.description AS description, m.time AS meetingTime FROM matches AS m LEFT JOIN locations AS l ON locationID=l.id LEFT JOIN users AS u ON (u.id=m.user2ID) WHERE m.user1ID=2 The first 3 lines of each sub-statement divided by UNION are identical. How can I abide by the DRY principle, not repeat those three lines, and make this query more concise?

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  • Escaping comma in java

    - by prasanna
    I have a string which is fed into the query as IN clause,which looks like this ('ACT','INACT') which is one of the parameters to a function inside a package.when a call is made to the function from java, it looks like this call package.function(1,2,3,('ACT','INACT'),4,5). When the package is called,i get error as wrong type of arguments. It is taking the values inside brackets as different values delimited by strings

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  • Looking for MSSQL Table Design Sanity Check for Profile Tables with Dynamic Columns.

    - by Code Sherpa
    I just want a general sanity check regarding database design. We are building a web system that has both Teachers and Students. Both have accounts in the system. Both have profiles in the system. My question is about the table design of those Profile tables. The Teacher profile is pretty static regarding the metadata associated with it. Each teacher has a set number of fields that exposes information about that individual (schools, degrees, etc). The students, however, are a different case. We are using a windows service to pull varying data about the students from an endless stream of excel spreadsheets. The data gets moved into our database and then the fields appear in association with the student's profile. Accordingly, each and every student may have very different fields in their profile. I originally started with the concept of three tables: Accounts ---------- AccountID TeacherProfiles ---------- TeacherProfileID AccountID SecondarySchool University YearsTeaching Etc... StudentProfiles ---------- StudentProfileID AccountID Header Value The StudentProfiles table would hold the name of the column headers from the excel spreadsheets and the associated values. I have since evolved the design a little to treat Profiles more generically per the attached ERD image. The Teacher and Student "Headers" are stored in a table called "ProfileAttributeTypes" and responses (either from the excel document or via input fields on the web form) are put in a ProfileAttributes table. This way both Student and Teacher profiles can be associated with a dynamic flow of profile fields. The "Permissions" table tells us whether we are dealing with a Student or a Teacher. Since this system is likely to grow quickly, I want to make sure the foundation is solid. Can you please provide feedback about this design and let me know if it seems sound or if you could see problems it might create and, if so, what might be a better approach? Thanks in advance.

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  • How to handle Foreign key for optional field in .NET

    - by brz dot net
    What is the best way to handle following situation? A dropdown(for master table) is optional in a particular form. But, In database table the field is constrained with foreign key. If user don't select from dropdown then It creates problem because of foreign key. One solution is to create default option in master table and use it in case of blank selection. but in dropdown, we need to handle this to show on top. Is it perfect solution? Is there any other optimized solution for this? Thanks

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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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  • Database Design Question: GUID + Natural Numbers

    - by Alan
    For a database I'm building, I've decided to use natural numbers as the primary key. I'm aware of the advantages that GUID's allow, but looking at the data, the bulk of row's data were GUID keys. I want to generate XML records from the database data, and one problem with natural numbers is that I don't want to expose my database key's to the outside world, and allow users to guess "keys." I believe GUID's solve this problem. So, I think the solution is to generate a sparse, unique iD derived from the natural ID (hopefully it would be 2-way), or just add an extra column in the database and store a guid (or some other multibyte id) The derived value is nicer because there is no storage penalty, but it would be easier to reverse and guess compared to a GUID. I'm (buy) curious as to what others on SO have done, and what insights they have.

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  • Why might one app connect to SQL backend OK and a second app fail if they share the same connectionstring?

    - by hawbsl
    Trying to figure out a SQL connection error 26 in our app. We've got two closely related apps Foo and FooAddIn. Foo is a Winforms app built in VS2010 and runs fine and connects fine to our SQLExpress back end. FooAddIn is an Outlook AddIn which references Foo.exe and connects to the same SQL Express instance. Or rather, it doesn't connect, instead reporting: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) Now, both apps share the same connectionstring and we've verified they really do share the same connectionstring. At this stage we're just testing from within the same developer machine, so the apps are on the same machine, going via the same VS2010 IDE. So a lot of the advice online for this error doesn't apply because the fact that Foo connects through to SQL Express tells us the database is there and available and can be reached. What else is there to check? One thing is that Foo and FooAddIn are running different runtime versions of System.Data (v2.0.50727 and v4.0.30319). Could that be a factor?

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  • Need to use query column value in nested subquery

    - by Dustin
    It seems I cannot use a column from the parent query in a sub query. How can I refactor this query to get what I need? dbo.func_getRelatedAcnts returns a table of related accounts (all children from a given account). Events and Profiles are related to accounts. SELECT COUNT(r.reg_id) FROM registrations r JOIN profiles p ON (r.reg_frn_pro_id = p.pro_id) JOIN events e ON (r.reg_frn_evt_id = e.evt_id) WHERE evt_frn_acnt_id NOT IN (SELECT * FROM dbo.func_getRelatedAcnts(p.pro_frn_acnt_id))

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  • FluentNHibernate error -- "Invalid object name"

    - by goober
    I'm attempting to do the most simple of mappings with FluentNHibernate & Sql2005. Basically, I have a database table called "sv_Categories". I'd like to add a category, setting the ID automatically, and adding the userid and title supplied. Database table layout: CategoryID -- int -- not-null, primary key, auto-incrementing UserID -- uniqueidentifier -- not null Title -- varchar(50) -- not null Simple. My SessionFactory code (which works, as far as I can tell): _SessionFactory = Fluently.Configure().Database( MsSqlConfiguration.MsSql2005 .ConnectionString(c => c.FromConnectionStringWithKey("SVTest"))) .Mappings(x => x.FluentMappings.AddFromAssemblyOf<CategoryMap>()) .BuildSessionFactory(); My ClassMap code: public class CategoryMap : ClassMap<Category> { public CategoryMap() { Id(x => x.ID).Column("CategoryID").Unique(); Map(x => x.Title).Column("Title").Not.Nullable(); Map(x => x.UserID).Column("UserID").Not.Nullable(); } } My Class code: public class Category { public virtual int ID { get; private set; } public virtual string Title { get; set; } public virtual Guid UserID { get; set; } public Category() { // do nothing } } And the page where I save the object: public void Add(Category catToAdd) { using (ISession session = SessionProvider.GetSession()) { using (ITransaction Transaction = session.BeginTransaction()) { session.Save(catToAdd); Transaction.Commit(); } } } I receive the error Invalid object name 'Category'. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Data.SqlClient.SqlException: Invalid object name 'Category'. I think it might be that I haven't told the CategoryMap class to use the "sv_Categories" table, but I'm not sure how to do that. Any help would be appreciated. Thanks!

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  • acts-as-taggable-on: find tags with name LIKE, sort by tag_counts?

    - by James
    Hi I'm using the rails plugin acts-as-taggable-onand I'm trying to find the top 5 most used tags whose names match and partially match a given query. When I do User.skill_counts.order('count DESC').limit(5).where('name LIKE ?', params[:query]) This return the following error: ActiveRecord::StatementInvalid: SQLite3::SQLException: ambiguous column name: name: SELECT tags.*, COUNT(*) AS count FROM "tags" INNER JOIN users ON users.id = taggings.taggable_id LEFT OUTER JOIN taggings ON tags.id = taggings.tag_id AND taggings.context = 'skills' WHERE (taggings.taggable_type = 'User') AND (taggings.taggable_id IN(SELECT users.id FROM "users")) AND (name LIKE 'asd') GROUP BY tags.id, tags.name HAVING COUNT(*) > 0 ORDER BY count DESC LIMIT 5 But when I do User.skill_counts.first.name this returns "alliteration" I'd appreciate any help on this matter.

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  • Storing object into cache using Linq classes and velocity

    - by Arun
    I careated couple of linq classes & marked the datacontext as unidirectional. Out of four classes; one is main class while other three are having the one to many relationship with first one; When I load the object of main class & put into the memory OR serialize it into an XML file; I never get the child class data while it is maked as DataContractAttribute. How can I force object to put the child class data into XML file or into cache ?

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  • MySQL, return only rows where there are duplicates among two columns.

    - by Richard Waite
    I have a table in MySQL of contact information ; first name, last name, address, etc. I would like to run a query on this table that will return only rows with first and last name combinations which appear in the table more than once. I do not want to group the "duplicates" (which may only be duplicates of the first and last name, but not other information like address or birthdate) - I want to return all the "duplicate" rows so I can look over the results and determine if they are dupes or not. This seemed like it would be a simple thing to do, but it has not been. Every solution I can find either groups the dupes and gives me a count only (which is not useful for what I need to do with the results) or doesn't work at all. Is this kind of logic even possible in a query ? Should I try and do this in Python or something?

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  • Returning a recordcount from a subquery in a result set.

    - by KeRiCr
    I am attempting to return a rowcount from a subquery as part of a result set. Here is a sample that I've tried that didn't work: SELECT recordID , GroupIdentifier , count() AS total , (SELECT COUNT() FROM table WHERE intActingAsBoolean = 1) AS Approved FROM table WHERE date_format(Datevalue, '%Y%m%d') BETWEEN 'startDate' AND 'endDate' GROUP BY groupIdentifier What I'm attempting to return for 'Approved' is the number of records for the grouped value where intActingAsBoolean = 1. I have also tried modifying the where clause by giving the main query a table alias and applying an AND clause to match the groupidentifier in the subquery to the main query. None of these are returning the correct results. The query as written returns all records in the table where intActingAsBoolean = 1. This query is being run against a MySQL database.

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  • data filter using dataloadoptions

    - by Tassadaque
    Using dataloadoptions i have tried the following example Northwnd db = new Northwnd(@"northwnd.mdf"); // Preload Orders for Customer. // One directive per relationship to be preloaded. DataLoadOptions ds = new DataLoadOptions(); ds.LoadWith<Customer>(c => c.Orders); ds.AssociateWith<Customer> (c => c.Orders.Where(p => p.ShippedDate != DateTime.Today)); db.LoadOptions = ds; var custQuery = from cust in db.Customers where cust.City == "London" select cust; foreach (Customer custObj in custQuery) { Console.WriteLine("Customer ID: {0}", custObj.CustomerID); foreach (Order ord in custObj.Orders) { Console.WriteLine("\tOrder ID: {0}", ord.OrderID); foreach (OrderDetail detail in ord.OrderDetails) { Console.WriteLine("\t\tProduct ID: {0}", detail.ProductID); } } } Now i need to ask how can i display Category ID and Category Name of the productID (i am supposing that One product can be in at most one category) by extending the above example Regards

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  • SQLException: incorrect syntax near '2'.

    - by Tobechukwu Ezenachukwu
    whenever I call the "ExecuteNonQuery" command on the following CommandText, I get the above SQLException myCommand.CommandText = "INSERT INTO fixtures (round_id, matchcode, date_utc, time_utc, date_london, time_london, team_A_id, team_A, team_A_country, team_B_id, team_B, team_B_country, status, gameweek, winner, fs_A, fs_B, hts_A, hts_B, ets_A, ets_B, ps_A, ps_B, last_updated) VALUES (" _ & round_id & "," & match_id & "," & date_utc & ",'" & time_utc & "'," & date_london & ",'" & time_london & "'," & team_A_id & ",'" & team_A_name & "','" & team_A_country & "'," & team_B_id & ",'" & team_B_name & "','" & _ team_B_country & "','" & status & "'," & gameweek & ",'" & winner & "'," & fs_A & "," & fs_B & "," & hts_A & "," & hts_B & "," & ets_A & "," & ets_B & "," & ps_A & "," & ps_B & "," & last_updated & ")" But whenever, i remove the last table item - "last_updated", the error disappears. Please help me resolve this issue. Is there any special treatment to be given to datetime fields??? Thanks for your help

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  • Migrating Data to MSSQL 2008

    - by Fred Clown
    I am trying to migrate data from an Informix database to MSSQL 2008. I've got quite a lot of data to move. I've been try multiple methods to get the data over, and so far SQLBulkCopy in multiple chunks seems to be the fastest that I can find. Does anyone know of a faster means of getting the data over? I'm trying to cut down on the transfer time so that on my cut-over date I don't run out of time to do the full cut-over. Thanks.

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  • Does AsEnumerable() cache all result (LINQ)

    - by Akshay
    When we call a query operator on a sequence, a sequence-specific operator gets called. I mean if i call Where<>() operator on IEnumerable<>, the operator that will be called will be defined in Enumerable class and if it's called on IQueryable<>, the one defined in Queryable class will be called. Consider the operator Reverse, defined in the Enumerable class. If i want to call it on Iqueryable<> then I must use the AsEnumerable<>() operator to first convert it into IEnumerable<>. db.Countries.OrderBy(cntry=>cntry.CountryName).AsEnumerable().Reverse() But the Reverse operator got to have all records at the same time so that it can reverse them. In the above code do all the records get loaded in memory first and then the Reverse() operator is reversing it ?

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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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  • Migrating from mssql to firebird: pro and cons

    - by user193655
    i am considering the migration for 3 reasons: 1) SQLSERVER installation is a nightmar, expecially for 1-user software. Software installs in 10 seconds, SQLServer in 1 hour. Firebird installation is much easier. 2) SQLSERVER runs on windows server only 3) My customers have all the express edition 4) i am not using any advanced feature, I am now starting using filestream, but the main reason for this is that Express eidtion has 4/10GB db size limit So these are all Pros of moving to Firebird. Which are the cons? I can also plan to support both platiforms, but this will backfire I fear.

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  • DB Interface Design Optimization: Is it better to optimise for Fewer requests of smaller data size?

    - by Overflow
    The prevailing wisdom in webservices/web requests in general is to design your api such that you use as few requests as possible, and that each request returns therefore as much data as is needed In database design, the accepted wisdom is to design your queries to minimise size over the network, as opposed to minimizing the number of queries. They are both remote calls, so what gives?

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  • PHP - Language Data

    - by bobrusha
    What's the best way to store language data? Keep it as variables in some kind of lang.php file... $l_ipsum = 'smth'; $l_rand = 'string'; Or select them from a database? I'm in search of your advice.

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