Search Results

Search found 27519 results on 1101 pages for 'sql learner'.

Page 618/1101 | < Previous Page | 614 615 616 617 618 619 620 621 622 623 624 625  | Next Page >

  • Looking for books

    - by robblot
    When I was learning Visual Basic.net 2008 I found a book that not only taught the basics but by the end of the book I had developed a fully working database application. Does anyone know where I might find a simular book but using Visual C++?

    Read the article

  • 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 ?

    Read the article

  • Checking for reciprocal relationships in mysql. A trivial one table problem.

    - by calumbrodie
    I have a mysql table that stores relationships. Items can be related to another item in one direction, or both items can be related to each other. I want to return all items related to my primary item - but I also want to check to see if the related item has a 'reverse relationship' to the current item and show this as a boolean |--------------|---------------| | SKU | related_SKU | |--------------|---------------| | 0001 | 0099 | | 0002 | 0099 | | 0099 | 0001 | |--------------|---------------| If I want to get all relationships for SKU=0001 SELECT related_SKU from relationships where SKU='0001' returns |--------------| | related_SKU | |--------------| | 0099 | |--------------| but what I want is |--------------|---------------| | related_SKU | reciprocal | |--------------|---------------| | 0099 | 1 | |--------------|---------------| or SELECT related_SKU from relationships where SKU='0002' |--------------|---------------| | related_SKU | reciprocal | |--------------|---------------| | 0099 | 0 | |--------------|---------------| What's the best way to do this?

    Read the article

  • How can I do more than one level of cascading deletes in Linq?

    - by Gary McGill
    If I have a Customers table linked to an Orders table, and I want to delete a customer and its corresponding orders, then I can do: dataContext.Orders.DeleteAllOnSubmit(customer.Orders); dataContext.Customers.DeleteOnSubmit(customer); ...which is great. However, what if I also have an OrderItems table, and I want to delete the order items for each of the orders deleted? I can see how I could use DeleteAllOnSubmit to cause the deletion of all the order items for a single order, but how can I do it for all the orders?

    Read the article

  • Question about joins and table with Millions of rows

    - by xRobot
    I have to create 2 tables: Magazine ( 10 millions of rows with these columns: id, title, genres, printing, price ) Author ( 180 millions of rows with these columns: id, name, magazine_id ) . Every author can write on ONLY ONE magazine and every magazine has more authors. So if I want to know all authors of Motors Magazine, I have to use this query: SELECT * FROM Author, Magazine WHERE ( Author.id = Magazine.id ) AND ( genres = 'Motors' ) The same applies to Printing and Price column. To avoid these joins with tables of millions of rows, I thought to use this tables: Magazine ( 10 millions of rows with this column: id, title, genres, printing, price ) Author ( 180 millions of rows with this column: id, name, magazine_id, genres, printing, price ) . and this query: SELECT * FROM Author WHERE genres = 'Motors' Is it a good approach ? I can use Postgresql or Mysql.

    Read the article

  • error invoking store procedure with input parameter from ADO.Net

    - by George2
    Hello everyone, I am using VSTS 2008 + C# + .Net 3.5 + ADO.Net. Here is my code and related error message. The error message says, @Param1 is not supplied, but actually it is supplied in my code. Any ideas what is wrong? System.Data.SqlClient.SqlException: Procedure or function 'Pr_Foo' expects parameter '@Param1', which was not supplied. class Program { private static SqlCommand _command; private static SqlConnection connection; private static readonly string _storedProcedureName = "Pr_Foo"; private static readonly string connectionString = "server=.;integrated Security=sspi;initial catalog=FooDB"; public static void Prepare() { connection = new SqlConnection(connectionString); connection.Open(); _command = connection.CreateCommand(); _command.CommandText = _storedProcedureName; _command.CommandType = CommandType.StoredProcedure; } public static void Dispose() { connection.Close(); } public static void Run() { try { SqlParameter Param1 = _command.Parameters.Add("@Param1", SqlDbType.Int, 300101); Param1.Direction = ParameterDirection.Input; SqlParameter Param2 = _command.Parameters.Add("@Param2", SqlDbType.Int, 100); portal_SiteInfoID.Direction = ParameterDirection.Input; SqlParameter Param3 = _command.Parameters.Add("@Param3", SqlDbType.Int, 200); portal_RoleInfoID.Direction = ParameterDirection.Input; _command.ExecuteScalar(); } catch (Exception e) { Console.WriteLine(e); } } static void Main(string[] args) { try { Prepare(); Thread t1 = new Thread(Program.Run); t1.Start(); t1.Join(); Dispose(); } catch (Exception ex) { Console.WriteLine(ex.Message + "\t" + ex.StackTrace); } } } thanks in avdance, George

    Read the article

  • Passing in a lambda to a Where statement

    - by sonicblis
    I noticed today that if I do this: var items = context.items.Where(i => i.Property < 2); items = items.Where(i => i.Property > 4); Once I access the items var, it executes only the first line as the data call and then does the second call in memory. However, if I do this: var items = context.items.Where(i => i.Property < 2).Where(i => i.Property > 4); I get only one expression executed against the context that includes both where statements. I have a host of variables that I want to use to build the expression for the linq lambda, but their presence or absence changes the expression such that I'd have to have a rediculous number of conditionals to satisfy all cases. I thought I could just add the Where() statements as in my first example above, but that doesn't end up in a single expression that contains all of the criteria. Therefore, I'm trying to create just the lambda itself as such: //bogus syntax if (var1 == "something") var expression = Expression<Func<item, bool>>(i => i.Property == "Something); if (var2 == "somethingElse") expression = expression.Where(i => i.Property2 == "SomethingElse"); And then pass that in to the where of my context.Items to evaluate. A) is this right, and B) if so, how do you do it?

    Read the article

  • 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 ;

    Read the article

  • 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?

    Read the article

  • mysqli_stmt_bind_param SQL Injection

    - by profitphp
    Is there still an injection risk when using prepared statements and mysqli_stmt_bind_param? For example: $malicious_input = 'bob"; drop table users'; mysqli_stmt_bind_param($stmt, 's', $malicious_input); Behind the scenes does mysqli_stmt_bind_param pass this query string to mysql: SET @username = "bob"; drop table users"; Or does it perform the SET command through the API, or use some type of protection to keep this from happening?

    Read the article

  • SqlServer2008 + expensive union all

    - by Tim Mahy
    Hi al, we have 5 tables over which we should query with user search input throughout a stored procedure. We do a union all of the similar data inside a view. Because of this the view can not be materialized. We are not able to change these 5 tables drastically (like creating a 6th table that contains the similar data of the 5 tables and reference that new one from the 5 tables). The query is rather expensive / slow what are our other options? It's allowed to think outside the box. Unfortunately I cannot give more information like the table/view/SP definition because of customer confidentiality... greetings, Tim

    Read the article

  • How do I create a stored procedure that calls sp_refreshview for each view in the database?

    - by Allrameest
    Today I run this select 'exec sp_refreshview N''['+table_schema+'].['+table_name+']''' from information_schema.tables where table_type = 'view' This generates a lot of: exec sp_refreshview N'[SCHEMA].[TABLE]'. I then copy the result to the query editor window and run all those execs. How do I do this all at once? I would like to have a stored procedure called something like dev.RefreshAllViews which I can execute to do this...

    Read the article

  • Single Query returning me 4 tables, How to get all of them back into dataset ?

    - by Shantanu Gupta
    How to fill multiple tables in a dataset. I m using a query that returns me four tables. At the frontend I am trying to fill all the four resultant table into dataset. Here is my Query. Query is not complete. But it is just a refrence for my Ques Select * from tblxyz compute sum(col1) suppose this query returns more than one table, I want to fill all the tables into my dataset I am filling result like this con.open(); adp.fill(dset); con.close(); Now when i checks this dataset. It shows me that it has four tables but only first table data is being displayed into it. rest 3 dont even have schema also. What i need to do to get desired output

    Read the article

  • 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 !

    Read the article

  • Linq with a long where clause

    - by Jeremy Roberts
    Is there a better way to do this? I tried to loop over the partsToChange collection and build up the where clause, but it ANDs them together instead of ORing them. I also don't really want to explicitly do the equality on each item in the partsToChange list. var partsToChange = new Dictionary<string, string> { {"0039", "Vendor A"}, {"0051", "Vendor B"}, {"0061", "Vendor C"}, {"0080", "Vendor D"}, {"0081", "Vendor D"}, {"0086", "Vendor D"}, {"0089", "Vendor E"}, {"0091", "Vendor F"}, {"0163", "Vendor E"}, {"0426", "Vendor B"}, {"1197", "Vendor B"} }; var items = new List<MaterialVendor>(); foreach (var x in partsToChange) { var newItems = ( from m in MaterialVendor where m.Material.PartNumber == x.Key && m.Manufacturer.Name.Contains(x.Value) select m ).ToList(); items.AddRange(newItems); } Additional info: I am working in LINQPad.

    Read the article

  • Adding a computed column to an ActiveRecord query

    - by bmwbzz
    Hi, I am running a query using a scope and some conditions. Something like this: conditions[:offset] = (options[:page].to_i - 1) * PAGE_SIZE unless options[:page].blank? conditions[:limit] = options[:limit] ||= PAGE_SIZE scope = Promo.enabled.active results = scope.all conditions I'd like to add a computed column to the query (at the point when I'm now calling scope.all). Something like this: (ACOS(least(1,COS(0.71106459055501)*COS(-1.2915436464758)*COS(RADIANS(addresses.lat))*COS(RADIANS(addresses.lng))+ COS(0.71106459055501)*SIN(-1.2915436464758)*COS(RADIANS(addresses.lat))*SIN(RADIANS(addresses.lng))+ SIN(0.71106459055501)*SIN(RADIANS(addresses.lat))))*3963.19) as accurate_distance Is there a way to do that without just using find_by_sql and rewriting the whole existing query? Thanks!

    Read the article

  • Linq issue retrieving single value from mssql

    - by Anicho
    Hey Guys, having an issue with linq, I am basically doing the following but it is saying it is "UserProfile does not contain definition for Username" in the current context where I wrote "u.Username" but it does exist I have added UserProfile table to MyDbml.dbml and if I connect to another table it works fine. TiamoDataContext context = new TiamoDataContext(); var user = (from u in context.UserProfiles where u.Username == UsernameLabel select u).FirstOrDefault(); I am flustered by what small detail I have missed out to get this to work, anyone have any clues it would be much appreciation.

    Read the article

  • HTML5 Web Database Security

    - by Daniel Dimovski
    Should the HTML5 database be used to store any form of private information? Say we have the following scenario; You're browsing a web-mail client, that uses the web database to store mail drafts after you've written some information you close the web browser. What's to stop me from getting access to this information? If the webpage tries to clean out old information when opened a user-script could easily prevent the website from fully loading and then search through the database. Furthermore the names of databases and tables are easily available through the web-mail client's source. W3C Draft

    Read the article

  • What are the reasons *not* to use a GUID for a primary key?

    - by Yarin
    Whenever I design a database I automatically start with an auto-generating GUID primary key for each of my tables (excepting look-up tables) I know I'll never lose sleep over duplicate keys, merging tables, etc. To me it just makes sense philosophically that any given record should be unique across all domains, and that that uniqueness should be represented in a consistent way from table to table. I realize it will never be the most performant option, but putting performance aside, I'd like to know if there are philosophical arguments against this practice?

    Read the article

  • How can I update a record using a correlated subquery?

    - by froadie
    I have a function that accepts one parameter and returns a table/resultset. I want to set a field in a table to the first result of that recordset, passing in one of the table's other fields as the parameter. If that's too complicated in words, the query looks something like this: UPDATE myTable SET myField = (SELECT TOP 1 myFunctionField FROM fn_doSomething(myOtherField) WHERE someCondition = 'something') WHERE someOtherCondition = 'somethingElse' In this example, myField and myOtherField are fields in myTable, and myFunctionField is a field return by fn_doSomething. This seems logical to me, but I'm getting the following strange error: 'myOtherField' is not a recognized OPTIMIZER LOCK HINTS option. Any idea what I'm doing wrong, and how I can accomplish this? *UPDATE: * Based on Anil Soman's answer, I realized that the function is expecting a string parameter and the field being passed is an integer. I'm not sure if this should be a problem as an explicit call to the function using an integer value works - e.g. fn_doSomething(12345) seems to automatically cast the number to an string. However, I tried to do an explicit cast: UPDATE myTable SET myField = (SELECT TOP 1 myFunctionField FROM fn_doSomething(CAST(myOtherField AS varchar(1000))) WHERE someCondition = 'something') WHERE someOtherCondition = 'somethingElse' Now I'm getting the following error: Line 5: Incorrect syntax near '('.

    Read the article

  • How Can I Reference Multiple Primary Keys For A Vector Type Primary Key

    - by AndreiC
    Hi, I have the following scenario: a table of projects and a table of persons, working on one or serveral projects. Also, I have a project id column (of type int), in the first table, which is a primary key there and I have a vector of project ids, as a column of type int, in my second table (persons), that references primary keys from the first table. What is the correct syntax for referencing multiple primary keys, from a vector foreign key. This is the way I am trying to create the table, but I am not sure what to place at the indicated line: CREATE TABLE Persons( Person_Id int, ..., ProjectsList int[], FOREIGN KEY (ProjectsList) REFERENCES Projects(Project_id) -- not sure what how to define the link here ); I hope my explanations are not over-complicated. Thank you in advance for helping!

    Read the article

  • how to Invoke User-Defined Functions That Return a Table Data Type

    - by nectar
    here my code- create function dbo.emptable() returns Table as return (select id, name, salary from employee) go select dbo.emptable() error: Msg 4121, Level 16, State 1, Line 1 Cannot find either column "dbo" or the user-defined function or aggregate "dbo.emptable", or the name is ambiguous. while when I run sp_helptext emptable it shows- create function dbo.emptable() returns Table as return (select id, name, salary from employee) it means function exists in database then why it is giving such error?

    Read the article

< Previous Page | 614 615 616 617 618 619 620 621 622 623 624 625  | Next Page >