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  • Lua SQL: peeking at cursors

    - by NP
    I am using LuaSQL, and query for a result set using con:execute(sql_stmt), which returns a cursor. How do I see if there is at least one row in that resultset, without doing a cursor:fetch to pop that first row?

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  • Should I return IEnumerable<T> or IQueryable<T> from my DAL?

    - by Gary '-'
    I know this could be opinion, but I'm looking for best practices. As I understand, IQueryable implements IEnumerable, so in my DAL, I currently have method signatures like the following: IEnumerable<Product> GetProducts(); IEnumerable<Product> GetProductsByCategory(int cateogoryId); Product GetProduct(int productId); Should I be using IQueryable here? What are the pros and cons of either approach? Note that I am planning on using the Repository pattern so I will have a class like so: public class ProductRepository { DBDataContext db = new DBDataContext(<!-- connection string -->); public IEnumerable<Product> GetProductsNew(int daysOld) { return db.GetProducts() .Where(p => p.AddedDateTime > DateTime.Now.AddDays(-daysOld )); } } Should I change my IEnumerable<T> to IQueryable<T>? What advantages/disadvantages are there to one or the other?

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  • MSSQL 2005: Rename DB Server Instance Name?

    - by Code Sherpa
    Hi, Can somebody tell me how to rename the DB server instance name and a DB name in MSSQL 2005? Right Now I Have SERVER/OLDNAME -- oldnameDB I want to change the server instance and also change the db name. I have tried: EXEC sp_renamedb 'oldName', 'newName' and that has changed the dbname as it appers in the tree directory. But, when I do "select @@servername" it is the old name. Also, the MDF and LDF files are still the old name. How do change instance and db names as a clean sweep across the server? Thanks.

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  • Survey Data Model - How to avoid EAV and excessive denormalization?

    - by AlexDPC
    Hi everyone, My database skills are mediocre at best and I have to design a data model for survey data. I have spent some thoughts on this and right now I feel that I am stuck between some kind of EAV model and a design involving hundreds of tables, each with hundreds of columns (and thousands of records). There must be a better way to do this and I hope that the wise folks on this forum can help me. I have already searched various forums, but I couldn't really find a solution. If it has already been given elsewhere, please excuse me and provide me with a link so I can read it up. Some assumptions about the data I have to deal with: Each survey consists of 1 to n questionnaires Each questionnaire consists of 100-2,000 questions (please ignore that 2,000 questions really sound like a lot to answer...) Questions can be of various types: multiple-choice, free text, a number (like age, income, percentages, ...) Each survey involves 10-200 countries (These are not the respondents. The respondents are actually people in the countries.) Depending on the type of questionnaire, each questionnaire is answered by 100-20,000 respondents per country. A country can adapt the questionnaires for a survey, i.e. add, remove or edit questions The data for one country is gathered in a separate database in that country. There is no possibility for online integration from the start. The data for all countries has to be integrated later. This means for example, if a country has deleted a question, that data must somehow be derived from what they sent in order to achieve a uniform design across all countries I will have to write the integration and cleaning software, which will need to work with every country's data In the end the data needs to be exported to flat files, one rectangular grid per country and questionnaire. I have already discussed this topic with people from various backgrounds and have not come to a good solution yet. I mainly got two kinds of opinions. The domain experts, who are used to working with flat files (spreadsheet-style) for data processing and analysis vote for a denormalized structure with loads of tables and columns as I described above (1 table per country and questionnaire). This sounds terrible to me, because I learned that wide tables are to be avoided, it will be annoying to determine which columns are actually in a table when working with it, the database will become cluttered with hundreds of tables (or I even need to set up multiple databases, each with a similar yet a bit differetn design), etc. O-O-programmers vote for a strongly "normalized" design, which would effectively lead to a central table containing all the answers from all respondents to all questions. This table would either need to contain a column of type sql_variant type or multiple answer columns with different types to store answers of different types (multiple choice, free text, ..). The former would essentially be a EAV model. I tend to follow Joe Celko here, who strongly discourages its use (he calls it OTLT or "One True Lookup Table"). The latter would imply that each row would contain null cells for the not applicable types by design. Another alternative I could think of would be to create one table per answer type, i.e., one for multiple-choice questions, one for free text questions, etc.. That's not so generic, it would lead to a lot of union joins, I think and I would have to add a table if a new answer type is invented. Sorry for boring you with all this text and thank you for your input! Cheers, Alex PS: I asked the same question here: http://www.eggheadcafe.com/community/aspnet/13/10242616/survey-data-model--how-to-avoid-eav-and-excessive-denormalization.aspx

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  • symfony 2 verify type of data stored in a single column

    - by GRafoKI
    In my DB I have a column 'own_product' that contains 2 values ( quantity and name) In my Edit form I want to check if the first field (quantity) is string and positive or not. I added a new column 'type-prod' (int , string) this is my controller : $request = $this->container->get('request'); if ($request->getMethod() == 'POST') { $formel = $request->query->get('edit_formal'); $type_value = $formel['own_product']; //case int $type_int= $this ->getDoctrine() ->getEntityManager() ->getRepository('DHG\WelcomeBundle\Entity\type-prod') ->findOneBy(array('type' => 'int')); //case string $type_string = $this ->getDoctrine() ->getEntityManager() ->getRepository('DHG\WelcomeBundle\Entity\type-prod') ->findOneBy(array('type' => 'string')); if (isset($type_value) && $type_int && $type_value > 0 && is_int($type_value)) { echo 'Success'; } else echo 'error' ; } Thank you !

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  • How to return a record from function executed by INSERT/UPDATE rule?

    - by seas
    Do the following scheme for my database: create sequence data_sequence; create table data_table { id integer primary key; field varchar(100); }; create view data_view as select id, field from data_table; create function data_insert(_new data_view) returns data_view as $$declare _id integer; _result data_view%rowtype; begin _id := nextval('data_sequence'); insert into data_table(id, field) values(_id, _new.field); select * into _result from data_view where id = _id; return _result; end; $$ language plpgsql; create rule insert as on insert to data_view do instead select data_insert(new); Then type in psql: insert into data_view(field) values('abc'); Would like to see something like: id | field ----+--------- 1 | abc Instead see: data_insert ------------- (1, "abc") Is it possible to fix this somehow? Thanks for any ideas. Ultimate idea is to use this in other functions, so that I could obtain id of just inserted record without selecting for it from scratch. Something like: insert into data_view(field) values('abc') returning id into my_variable would be nice but doesn't work with error: ERROR: cannot perform INSERT RETURNING on relation "data_view" HINT: You need an unconditional ON INSERT DO INSTEAD rule with a RETURNING clause. I don't really understand that HINT. I use PostgreSQL 8.4.

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  • When should I consider representing the primary-key ...?

    - by JMSA
    When should I consider representing the primary-key as classes? Should we only represent primary keys as classes when a table uses composite-key? For example: public class PrimaryKey { ... ... ...} Then private PrimaryKey _parentID; public PrimaryKey ParentID { get { return _parentID; } set { _parentID = value; } } And public void Delete(PrimaryKey id) {...} When should I consider storing data as comma-separated values in a column in a DB table rather than storing them in different columns?

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  • Does clustered index on foreign key column increase join performance vs non-clustered ?

    - by alpav
    In many places it's recommended that clustered indexes are better utilized when used to select range of rows using BETWEEN statement. When I select joining by foreign key field in such a way that this clustered index is used, I guess, that clusterization should help too because range of rows is being selected even though they all have same clustered key value and BETWEEN is not used. Considering that I care only about that one select with join and nothing else, am I wrong with my guess ?

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  • Observing social web behavior: to log or populate databases?

    - by jlafay
    When considering social web app architecture, is it a better approach to document user social patterns in a database or in logs? I thought for sure that behavior, actions, events would be strictly database stored but I noticed that some of the larger social sites out there also track a lot by logging what happens. Is it good practice to store prominent data about users in a database and since thousands of user actions can be spawned easily, should they be simply logged?

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  • Adding Silverlight pages to existing ASP.net page??

    - by AJ
    Hi I know how to add SL page as a whole to existing ASP.net application. We have existing ASP.net page with few tabs. Each tab is a user control. We want to add another tab, which will host Silverlight content. Is it possible to add silverlight content in one of the tabs of a page? Any example links? Another way of putting up the same question : Is it possible to have an ASP.net page with top half as regular asp.net content and other half containing silverlight content? Please advise. Thanks AJ

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  • MDX: How to exclude ancestors from being returned in this query?

    - by wgpubs
    I have this MDX query: Exists([Group].[Group Hierarchy].allmembers, {[Group].[Group Full Name].&[121 - Group A], [Group].[Group Full Name].&[700000 - Group C]}) ... which works fine EXCEPT that it returns all of the ancestors of the specified groups as well. What I want is to return JUST the groups from the hierarchy with the specified Group Names (this is a type 2 dimension so there may be many at different levels). Any ideas?

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  • Conditionally set a column to its default value in Postgres

    - by Evgeny
    I've got a PostgreSQL 8.4 table with an auto-incrementing, but nullable, integer column. I want to update some column values and, if this column is NULL then set it to its default value (which would be an integer auto-generated from a sequence), but I want to return its value in either case. So I want something like this: UPDATE mytable SET incident_id = COALESCE(incident_id, DEFAULT), other = 'somethingelse' WHERE ... RETURNING incident_id Unfortunately, this doesn't work - it seems that DEFAULT is special and cannot be part of an expression. What's the best way to do this?

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  • GridView will not update underlying data source

    - by John Christensen
    So I'm been pounding on this problem all day. I've got a LinqDataSource that points to my model and a GridView that consumes it. When I attempt to do an update on the GridView, it does not update the underlying data source. I thought it might have to do with the LinqDataSource, so I added a SqlDataSource and the same thing happens. The aspx is as follows (the code-behind page is empty): <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="Data Source=devsql32;Initial Catalog=Steam;Persist Security Info=True;" ProviderName="System.Data.SqlClient" SelectCommand="SELECT [LangID], [Code], [Name] FROM [Languages]" UpdateCommand="UPDATE [Languages] SET [Code]=@Code WHERE [LangID]=@LangId"> </asp:SqlDataSource> <asp:GridView ID="_languageGridView" runat="server" AllowPaging="True" AllowSorting="True" AutoGenerateColumns="False" DataKeyNames="LangId" DataSourceID="SqlDataSource1"> <Columns> <asp:CommandField ShowDeleteButton="True" ShowEditButton="True" /> <asp:BoundField DataField="LangId" HeaderText="Id" ReadOnly="True" /> <asp:BoundField DataField="Code" HeaderText="Code" /> <asp:BoundField DataField="Name" HeaderText="Name" /> </Columns> </asp:GridView> <asp:LinqDataSource ID="_languageDataSource" ContextTypeName="GeneseeSurvey.SteamDatabaseDataContext" runat="server" TableName="Languages" EnableInsert="True" EnableUpdate="true" EnableDelete="true"> </asp:LinqDataSource> What in the world am I missing here? This problem is driving me insane.

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  • MySQL Query: Winning Auction Bid

    - by mabwi
    I have a small Bidding system that I'm using for a fantasy auction draft. I'm trying to use the below query to pull up the max bids on each player. However, it's not actually giving me the max bid, it's just giving me the first one entered in to the database. SELECT Bid.id FROM bids AS Bid WHERE Bid.active =1 GROUP BY player_id HAVING MAX( Bid.amount ) Here's the Bid table layout, in case it helps: CREATE TABLE IF NOT EXISTS `bids` ( `id` int(10) NOT NULL AUTO_INCREMENT, `user_id` int(10) NOT NULL, `player_id` int(10) NOT NULL, `amount` int(6) NOT NULL, `timestamp` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, `winning_bid` int(1) NOT NULL DEFAULT '0', `active` int(1) NOT NULL DEFAULT '1', PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 ;

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  • Syntax for combining joins in mysql

    - by UltraVi01
    I seem to remember reading somewhere that there is a way to combine LEFT JOIN statements into a more simple query. I have the following query and was hoping someone could kindly take a look at it. SET @userId = 8; SELECT ug.user_id, COUNT(DISTINCT goal_id) as matches FROM user_goal ug, user u, profile p LEFT JOIN user_block ub ON @userId = ub.blocked_id LEFT JOIN user_block ub2 ON @userId = ub2.blocker_id LEFT JOIN user_user uu ON @userId = uu.user_id LEFT JOIN friend_request fr ON @userId = fr.user_id WHERE ug.user_id = u.id AND u.profile_id = p.id AND (ub.blocker_id IS NULL OR ub.blocker_id != ug.user_id) AND (ub2.blocked_id IS NULL OR ub2.blocked_id != ug.user_id) AND (uu.user_friends_id IS NULL OR uu.user_friends_id != ug.user_id) AND (fr.to_user_id IS NULL OR (fr.to_user_id != ug.user_id)) AND ug.user_id!=@userId AND p.suggestible AND goal_id IN (SELECT iug.goal_id FROM user_goal iug WHERE user_id=@userId) GROUP BY user_id ORDER BY matches DESC LIMIT 4

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  • same Linq for two tables

    - by Diana
    I need to do something like this, My two tables have the same signature, but different class so It suppose to work but it is not working. var myTable; if (booleanVariable == true) { myTable = table1; } else { myTable = table2; } var myLinq1 = from p in myTable join r in myOtherTable select p; In this case, I have to initialize myTable I have tried also, var myTable= table2; if (booleanVariable == true) { myTable = table1; } var myLinq1 = from p in myTable join r in myOtherTable select p; then var is type table2, then it can't be changed to table1 type. I need help, I don't want to make a copy paste of all the code. the linq query is huge, and it s nested with 5 or 6 queries. also I have to do this on 12 different methods. Thanks a lot for your help.

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  • How do I Put Several Select Statements into Different Columns

    - by Russ Bradberry
    I basically have 7 select statement that I need to have the results output into separate columns. Normally I would use a crosstab for this but I need a fast efficient way to go about this as there are over 7 billion rows in the table. I am using the vertica database system. Below is an example of my statements: SELECT COUNT(user_id) AS '1' FROM event_log_facts WHERE date_dim_id=20100101 SELECT COUNT(user_id) AS '2' FROM event_log_facts WHERE date_dim_id=20100102 SELECT COUNT(user_id) AS '3' FROM event_log_facts WHERE date_dim_id=20100103 SELECT COUNT(user_id) AS '4' FROM event_log_facts WHERE date_dim_id=20100104 SELECT COUNT(user_id) AS '5' FROM event_log_facts WHERE date_dim_id=20100105 SELECT COUNT(user_id) AS '6' FROM event_log_facts WHERE date_dim_id=20100106 SELECT COUNT(user_id) AS '7' FROM event_log_facts WHERE date_dim_id=20100107

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  • how to get external variable value in dtsx package.

    - by Rishabh
    Hi, I am executing .dtsx package from c#, it was executing fine, if i am passing one variable value from c# code then how can i get it on .dtsx package for my ole db source query. Here is my c# code. string file = @"D:\CYNCZFuzzy\CYNCZFuzzy\Contact.dtsx"; package = app.LoadPackage(file, null); Variables vars = package.Variables; vars["User::parentContactID"].Value = 1028203; pkgResults = package.Execute(); string result = pkgResults.ToString(); I need this 1028203 value on my ole db source query, here my query. select cr.MasterContactID as ParentContactID, c.ID,C.FirstName, C.MiddleName, c.LastName, c.ID as FieldID from Contact c inner join ContactRelation cr on cr.SlaveContactID = c.ID where RelationshipID = 1 AND cr.MasterContactID = ? what I should write on ? for getting 1028203 value from c# page. Thanks in advance...

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  • How can I perform this query between related tables without using UNION?

    - by jeremy
    Suppose I have two separate tables that I watch to query. Both of these tables has a relation with a third table. How can I query both tables with a single, non UNION based query? I want the result of the search to rank the results by comparing a field on each table. Here's a theoretical example. I have a User table. That User can have both CDs and books. I want to find all of that user's books and CDs with a single query matching a string ("awesome" in this example). A UNION based query might look like this: SELECT "book" AS model, name, ranking FROM book WHERE name LIKE 'Awesome%' UNION SELECT "cd" AS model, name, ranking FROM cd WHERE name LIKE 'Awesome%' ORDER BY ranking DESC How can I perform a query like this without the UNION? If I do a simple left join from User to Books and CDs, we end up with a total number of results equal to the number of matching cds timse the number of matching books. Is there a GROUP BY or some other way of writing the query to fix this?

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  • Best performance approach to history mechanism?

    - by Royi Namir
    We are going to create History Mechanism for our changes in DB (DART in pic) via Triggers. we have 600 tables. Each record that will be changed - the trigger will insert the deleted one into XXX. regarding to the XXX : option 1 : clone each table in "Dart" DB and each table now will have a "sister table" e.g. : Table1 will have Table1_History problems : we will have 1200 tables programmer can do mistakes by working on wrong tables... option 2 : make a new DB (DART_2005 in pic) and the history tables will be there option 3 : use linked server which stores the Db which will contain the history tables. question : 1) which option gives the best performance ( I guess 3 is not - but is it 1 or 2 or same ?) 2) Does option 2 is acting like "linked server" ( in queries we will need to select from both DB's...) 3) What is the best practice approach ?

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