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  • 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!

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  • How can i return dataset perfectly from sql?

    - by Phsika
    i try to write a winform application: i dislike below codes: DataTable dt = new DataTable(); dt.Load(dr); ds = new DataSet(); ds.Tables.Add(dt); Above part of codes looks unsufficient.How can i best loading dataset? public class LoadDataset { public DataSet GetAllData(string sp) { return LoadSQL(sp); } private DataSet LoadSQL(string sp) { SqlConnection con = new SqlConnection(ConfigurationSettings.AppSettings["ConnectionString"].ToString()); SqlCommand cmd = new SqlCommand(sp, con); DataSet ds; try { con.Open(); cmd.CommandType = CommandType.StoredProcedure; SqlDataReader dr = cmd.ExecuteReader(); DataTable dt = new DataTable(); dt.Load(dr); ds = new DataSet(); ds.Tables.Add(dt); return ds; } finally { con.Dispose(); cmd.Dispose(); } } }

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  • Linq ChangeConflictException (ASP.NET MVC) - occurs when submitting DataContext changes

    - by Alex
    System.Data.Linq.ChangeConflictException: 2 of X updates failed. at System.Data.Linq.ChangeProcessor.SubmitChanges(ConflictMode failureMode) at System.Data.Linq.DataContext.SubmitChanges(ConflictMode failureMode) at PROJECT.Controllers.HomeController.ClickProc(Int32 id, String code, String n) This is what I get very often. This action is done thousands of times a day, and I get this exception about once every 5 seconds. From what I understand it happens when something changes in the database in the period between creating DataContext and updating it. Am I right? What's the problem here and how can I fix it?

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  • When using Query Syntax in C# "Enumeration yielded no results". How to retrieve output

    - by Shantanu Gupta
    I have created this query to fetch some result from database. Here is my table structure. What exaclty is happening. DtMapGuestDepartment as Table 1 DtDepartment as Table 2 Are being used var dept_list= from map in DtMapGuestDepartment.AsEnumerable() where map.Field<Nullable<long>>("GUEST_ID") == DRowGuestPI.Field<Nullable<long>>("PK_GUEST_ID") join dept in DtDepartment.AsEnumerable() on map.Field<Nullable<long>>("DEPARTMENT_ID") equals dept.Field<Nullable<long>>("DEPARTMENT_ID") select dept.Field<string>("DEPARTMENT_ID"); I am performing this query on DataTables and expect it to return me a datatable. Here I want to select distinct department from Table 1 as well which will be my next quest. Please answer to that also if possible.

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  • 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?

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  • insert data to table based on another table C#

    - by user1017315
    I wrote a code which takes some values from one table and inserts the other table in these values.(not just these values, but also these values(this values=values from the based on table)) and I get this error: System.Data.OleDb.OleDbException (0x80040E10): value wan't given for one or more of the required parameters.` here's the code. I don't know what i've missed. string selectedItem = comboBox1.SelectedItem.ToString(); Codons cdn = new Codons(selectedItem); string codon1; int index; if (this.i != this.counter) { //take from the DataBase the matching codonsCodon1 to codonsFullName codon1 = cdn.GetCodon1(); //take the serialnumber of the last protein string connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;" + "Data Source=C:\\Projects_2012\\Project_Noam\\Access\\myProject.accdb"; OleDbConnection conn = new OleDbConnection(connectionString); conn.Open(); string last= "SELECT proInfoSerialNum FROM tblProInfo WHERE proInfoScienceName = "+this.name ; OleDbCommand getSerial = new OleDbCommand(last, conn); OleDbDataReader dr = getSerial.ExecuteReader(); dr.Read(); index = dr.GetInt32(0); //add the amino acid to tblOrderAA using (OleDbConnection connection = new OleDbConnection(connectionString)) { string insertCommand = "INSERT INTO tblOrderAA(orderAASerialPro, orderAACodon1) " + " values (?, ?)"; using (OleDbCommand command = new OleDbCommand(insertCommand, connection)) { connection.Open(); command.Parameters.AddWithValue("orderAASerialPro", index); command.Parameters.AddWithValue("orderAACodon1", codon1); command.ExecuteNonQuery(); } } } EDIT:I put a messagebox after that line: index = dr.GetInt32(0); to see where is the problem, and i get the error before that.i don't see the messagebox

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  • Creating a function in Postgresql that does not return composite values

    - by celenius
    I'm learning how to write functions in Postgresql. I've defined a function called _tmp_myfunction() which takes in an id and returns a table (I also define a table object type called _tmp_mytable) -- create object type to be returned CREATE TYPE _tmp_mytable AS ( id integer, cost double precision ); -- create function which returns query CREATE OR REPLACE FUNCTION _tmp_myfunction( id integer ) RETURNS SETOF _tmp_mytable AS $$ BEGIN RETURN QUERY SELECT id, cost FROM sales WHERE id = sales.id; END; $$ LANGUAGE plpgsql; This works fine when I use one id and call it using the following approach: SELECT * FROM _tmp_myfunction(402); What I would like to be able to do is to call it, but to use a column of values instead of just one value. However, if I use the following approach I end up with all values of the table in one column, separated by commas: -- call function using all values in a column SELECT _tmp_myfunction(t.id) FROM transactions as t; I understand that I can get the same result if I use SELECT _tmp_myfunction(402); instead of SELECT * FROM _tmp_myfunction(402); but I don't know how to construct my query in such a way that I can separate out the results.

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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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  • How to display SUM fields from a detailed table in a master table

    - by max
    What is the best approach to display the summery of DETAILED.Fields in its master table? E.g. I have a master table called 'BILL' with all the bill related data and a detailed table ('BILL_DETAIL') with the bill detailed related data, like NAME, PRICE, TAX, ... Now I want to list all BILLS, without the details, but with the sum of the PRICE and TAX stored in the detail table. Here is a simplified schema of that tables: TABLE BILL ---------- - ID - NAME - ADDRESS - ... TABLE BILL_DETAIL ----------------- - ID - BILLID - PORDUCT_NAME - PRICE - TAX - ... The retrieved table row should look like this: BILL.CUSTOMER_NAME, BILL.CUSTOMER_ADDRESS, sum(BILL_DETAIL.PRICE), sum(BILL.DETAIL.TAX), ... Any sugguestions?

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  • Ordering Wordpress posts by most recently commented on

    - by Hardseat
    What's the query to list wordpress posts by most recent, with posts most recently commented on going to the top of the order? (Standard "message board" style) This post looked promising: http://stackoverflow.com/questions/698438/ordering-wordpress-posts-by-most-recent-comment But the query is clearly wrong. Can anyone help?

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  • How to get an id from the results in two tables

    - by Chris Lively
    Consider an order. An order will have one or more line items. Each line item is for a particular product. Given a filter table with a couple of products, how would I get the order id's that had at least all of the products listed in the second table? table Orders( OrderId int ) table LineItems ( OrderId int, LineItemId int, ProductId int ) table Filter ( ProductId int ) data Orders OrderId -------- 1 2 3 LineItems OrderId LineItemId ProductId ------- ---------- --------- 1 1 401 1 2 502 2 3 401 3 4 401 3 5 603 3 6 714 Filter ProductId --------- 401 603 Desired result of the query: OrderId: 3

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  • how to query with child relations to same table and order this correctly

    - by robertpnl
    Hi, Take this table: id name sub_id --------------------------- 1 A (null) 2 B (null) 3 A2 1 4 A3 1 The sub_id column is a relation to his owm table, to column ID. subid --- 0:1 --- id Now I have the problem to make a correctly SELECT query to show that the child rows (which sub_id is not null) directly selected under his parent row. So this must be a correctly order: 1 A (null) 3 A2 1 4 A3 1 2 B (null) A normal SELECT order the id. But how or which keyword help me to order this correctly? JOIN isn't possible I think because I want to get all the rows seperated. Because the rows will be displayed on a Gridview (ASP.Net) with EntityDataSource but the child rows must be displayed directly under his parent. Thank you.

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  • Sub reports find the sub total and grand total of each sub report in the main report

    - by sonia
    i want to find the grand total from sub report subtotal. i have three subreports. 1. itemreport 2.laborreport 3. machine report. i have find total of that reports using shared variable. like using formula: shared numbervar totalitem=sum({storedprocedrename.columnname}) i have done dis in all the sbreports. now i m want the grand total of all these. i have written the formula in main report is: shared numbervar totalitem; // same variable used in subreport item shared numbervar labtotal; // same variable sed in subreport labor shared numbervar machinetotal; // same variable used in subreport machine numbervar total; total=totalitem+labtotal+machinetotal; total but it is not giving correct result.. it is not giving result in correct format plz tell me code of main report in detail.. thanks

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  • About to migrate :string but I'm thinking :text might be better. Performance/Purpose?

    - by Sam
    class CreateScrapes < ActiveRecord::Migration def self.up create_table :scrapes do |t| t.text :saved_characters t.text :sanitized_characters t.string :href t.timestamps end end def self.down drop_table :scrapes end end I'm about to rake db:migrate and I'm think about the attribute type if I should be using text or string. Since saved_characters and sanitized_characters will be arrays with thousands of unicode values, its basically comma delimited data, I'm not sure if `:text' is really the right way to go here. What would you do?

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  • Query next/previous record

    - by Rob
    I'm trying to find a better way to get the next or previous record from a table. Let's say I have a blog or news table: CREATE TABLE news ( news_id INT UNSIGNED NOT NULL PRIMARY KEY AUTO_INCREMENT, news_datestamp DATETIME NOT NULL, news_author VARCHAR(100) NOT NULL, news_title VARCHAR(100) NOT NULL, news_text MEDIUMTEXT NOT NULL ); Now on the frontend I want navigation buttons for the next or previous records, if i'm sorting by news_id, I can do something rather simple like: SELECT MIN(news_id) AS next_news_id FROM news WHERE news_id > '$old_news_id' LIMIT 1 SELECT MAX(news_id) AS prev_news_id FROM news WHERE news_id < '$old_news_id' LIMIT 1 But the news can be sorted by any field, and I don't necessarily know which field is sorted on, so this won't work if the user sorts on news_author for example. I've resorted to the rather ugly and inefficient method of sorting the entire table and looping through all records until I find the record I need. $res = mysql_query("SELECT news_id FROM news ORDER BY `$sort_column` $sort_way"); $found = $prev = $next = 0; while(list($id) = mysql_fetch_row($res)) { if($found) { $next = $id; break; } if($id == $old_news_id) { $found = true; continue; } $prev = $id; } There's got to be a better way.

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  • Good strategy for copying a "sliding window" of data from a table?

    - by chiborg
    I have a MySQL table from a third-party application that has millions of rows and only one index - the timestamp of each entry. Now I want to do some heavy self-joins and queries on the data using fields other than the timestamp. Doing the query on the original table would bring the database to a crawl, adding indexes to the table is not an option. Additionally, I only need entries that are newer than one week. My current strategy for doing the queries efficiently is to use a separate table (aux_table) that has the necessary indexes. My questions are: Is there another way to do the queries? and if not, How do I update the data in the indexed table efficiently? So far I have found two approaches for updating aux_table: Truncate aux_table and insert the desired data from the original table. Not very efficient because all the indexes must be re-crated. Check for the biggest timestamp in aux_table and insert all entries with a greater or equal timestamp from the original table. Occasionally drop older entries. Only copying entries with greater timestamp leads to dropped entries (because of entries with same timestamp that were inserted into the original table after the last update).

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  • 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?

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  • Are there more secure alternatives to the .Net SQLConnection class?

    - by KeyboardMonkey
    Hi SO people, I'm very surprised this issue hasn't been discussed in-depth: This article tells us how to use windbg to dump a running .Net process strings in memory. I spent much time researching the SecureString class, which uses unmanaged pinned memory blocks, and keeps the data encrypted too. Great stuff. The problem comes in when you use it's value, and assign it to the SQLConnection.ConnectionString property, which is of the System.String type. What does this mean? Well... It's stored in plain text Garbage Collection moves it around, leaving copies in memory It can be read with windbg memory dumps That totally negates the SecureString functionality! On top of that, the SQLConnection class is non-inheritable, I can't even roll my own with a SecureString property instead; Yay for closed-source. Yay. A new DAL layer is in progress, but for a new major version and for so many users it will be at least 2 years before every user is upgraded, others might stay on the old version indefinitely, for whatever reason. Because of the frequency the connection is used, marshalling from a SecureString won't help, since the immutable old copies stick in memory until GC comes around. Integrated Windows security isn't an option, since some clients don't work on domains, and other roam and connect over the net. How can I secure the connection string, in memory, so it can't be viewed with windbg?

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  • Can't get Sum() working in Northwind example

    - by Vince
    Hi, The following code is generating a runtime error and I have no idea why. from o in Orders group o by o.Employee into employeeOrders select new { employeeOrders.Key.EmployeeID, employeeOrders.Key.FirstName, Orders = from eord in employeeOrders orderby eord.OrderID select new { eord.OrderID, eord.OrderDate, OrderTotal=eord.OrderDetails.Sum (od => od.UnitPrice) } } The error is Member access 'System.Decimal UnitPrice' of 'LINQPad.User.OrderDetails' not legal on type 'LINQPad.User.Orders I've also tried this in VS2010 with a standard drag and drop data context and same thing. Thanks in advance

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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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