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• Complicated SQL query

  - by Yandawl

  Please bare with me this is difficult to explain xD http://img90.imageshack.us/i/croppercapture1.png/ This is based on an undergraduate degree course where a student takes many units (say 4 core units and 1 optional unit per year). tblAwardCoreUnits and tblAwardOptUnits store which units are optional and core for which award, hence the relationship to tblAward and tblStudentCoreUnits and tblStudentOptUnits store the particular instances of those units which a particular student is taking. Secondly, a unit can have multiple events (say a lecture and a unit) and each of those events has sessions in which a student can attend, hence tblEvents, tblSessions and tblAttendances. The query I am trying to produce is to get a list of all level one students, grouped by their award that lists the percentage of attendances in all the units in the current level. I've tried and tried with this and the following is the best I've managed to come up with so far... I'd REALLY appreciate any help you can give with this! SELECT tblStudents.enrolmentNo, tblStudents.forename, tblStudents.surname, tblAwards.title, (SELECT COUNT((tblAttendances.attended + tblAttendances.authorisedAbsence)) AS SumOfAttendances FROM tblAttendances INNER JOIN (tblStudents ON tblStudents.enrolmentNo = tblAttendances.enrolmentNo)) / FROM tblUnits, tblAwards INNER JOIN ((tblStudents INNER JOIN tblStudentOptUnit ON tblStudents.studentID = tblStudentOptUnit.studentID) INNER JOIN tblStudentCoreUnit ON tblStudents.studentID = tblStudentCoreUnit.studentID) ON tblAwards.awardID = tblStudents.awardID WHERE (((tblStudents.level)="1") AND ((tblStudents.status)="enrolled")) GROUP BY tblAwards.title ORDER BY tblStudents.forname;

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• Firebird: How to assign id to existing rows from newly added generator

  - by Aldo

  I have a table which already contains some rows and does not have a primary key. I want to add a primary key now, but for that I need to set unique values for the primary key field of the existing rows. How can this be done, using the newly added generator?

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• how do i connect to MSSQL 2008 database in JAVA with jbbc

  - by shuxer

  Hello I have MSSQL 2008 installed on my local PC, and my java application needs to connect to a mssql database. I am a new to MSSQL and i would like get some help on creating user login for my java application and getting connection via jdbc. So far i tried to create a user login for my app and used following connection string, but i doest work at all. Any help and hint will be appreciated. jdbc:jtds:sqlserver://127.0.0.1:1433/dotcms username="shuxer" password="itarator" Thanks in advance.

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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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• LINQ2SQL: how to merge two columns from the same table into a single list

  - by TomL

  this is probably a simple question, but I'm only a beginner so... Suppose I have a table containing home-work locations (cities) certain people use. Something like: ID(int), namePerson(string), homeLocation(string), workLocation(string) where homeLocation and workLocation can both be null. Now I want all the different locations that are used merged into a single list. Something like: var homeLocation = from hm in Places where hm.Home != null select hm.Home; var workLocation = from wk in Places where wk.Work != null select wk.Work; List<string> locationList = new List<string>(); locationList = homeLocation.Distinct().ToList<string>(); locationList.AddRange(workLocation.Distinct().ToList<string>()); (which I guess would still allow duplicates if they have the same value in both columns, which I don't really want...) My question: how this be put into a single LINQ statement? Thanks in advance for your help!

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• determine if a restaurant is open now (like yelp does) using database, php, js

  - by vee

  i was wondering if anyone knows how yelp determines what restaurants are "open now"? i'm developing a similar application using html/javascript/php. i was going to have a column in my database for each day, with comma separated hours written in "2243" format (10:43 pm). so for example if a restaurant is open for lunch and dinner it might be "1100,1400,1700,2200". then i'd check (using js) if the current time falls in one of the ranges for the current day. i'd also like to be able to determine if a restaurant is "open tonight", "open late", etc. for those i guess i'd check whether the open range overlaps with certain ranges. is there a better way to do this? particularly, how to store the hours in the database and then determine if they overlap with a given set of hours. thanks.

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• need help in c# for loops

  - by hala

  sory for that arabic part but i dont now englich much ?? ???? ?? ???? ???????? foreach(int i in array1) { Console.Writeln(i); } what is console ?? ???

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• What's faster? select [object] or select new {[object].value1, [object].value2} with linq

  - by Darcy

  I was hoping some of you guru's out there know the answer to this question. Which is faster? A or B A: var item = from d in database select d; B: var item = from d in database select new {d.item1, d.item2}; SEEMINGLY, it seems like selecting part of the table object would be faster than selecting the entire object, but something tells me its not necessarily the case.

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• MDX Year on Year Sales by Months

  - by schone

  Hi all, I'm stuck on a MDX query, I'm trying to retrieve the following results: [Time].[2009] [Time].[2010] [Time].[Months].Members [Measures].[Sales] [Measures].[Sales] So I would like to compare the sales which were in 2009 against 2010 by month. In terms of a chart I would have two series one for 2009 and 2010, the y axis would be the sales value and the x axis would be the month. Any ideas on how to approach this? Thanks in advance

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• Timeout LinqToSql inserting millions of records

  - by Bas

  I'm inserting approximently 3 million records in a database using this solution. Eventually when the application has been inserting records for a while (my last run lasted around 4 hours), it gives a timeout with the following SqlException: "SqlExcepetion: Timeout expired. The timeoutperiod elapsed prior to completion of the operation or the server is not responding." What's the best way to handle this exception? Is there a way to prevent this from happening or should I catch the exception? Thanks in advance!

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• Why isn't the Cache invalidated after table update using the SqlCacheDependency?

  - by Jason

  I have been trying to get SqlCacheDependency working. I think I have everything set up correctly, but when I update the table, the item in the Cache isn't invalidated. Can you look at my code and see if I am missing anything? I enabled the Service Broker for the Sandbox database. I have placed the following code in the Global.asax file. I also restart IIS to make sure it is called. void Application_Start(object sender, EventArgs e) { SqlDependency.Start(ConfigurationManager.ConnectionStrings["SandboxConnectionString"].ConnectionString); } I have placed this entry in the web.config file: <system.web> <caching> <sqlCacheDependency enabled="true" pollTime="10000"> <databases> <add name="Sandbox" connectionStringName="SandboxConnectionString"/> </databases> </sqlCacheDependency> </caching> </system.web> I call this code to put the item into the cache: protected void CacheDataSetButton_Click(object sender, EventArgs e) { using (SqlConnection sqlConnection = new SqlConnection(ConfigurationManager.ConnectionStrings["SandboxConnectionString"].ConnectionString)) { using (SqlCommand sqlCommand = new SqlCommand("SELECT PetID, Name, Breed, Age, Sex, Fixed, Microchipped FROM dbo.Pets", sqlConnection)) { using (SqlDataAdapter sqlDataAdapter = new SqlDataAdapter(sqlCommand)) { DataSet petsDataSet = new DataSet(); sqlDataAdapter.Fill(petsDataSet, "Pets"); SqlCacheDependency petsSqlCacheDependency = new SqlCacheDependency(sqlCommand); Cache.Insert("Pets", petsDataSet, petsSqlCacheDependency, DateTime.Now.AddSeconds(10), Cache.NoSlidingExpiration); } } } } Then I bind the GridView with this code: protected void BindGridViewButton_Click(object sender, EventArgs e) { if (Cache["Pets"] != null) { GridView1.DataSource = Cache["Pets"] as DataSet; GridView1.DataBind(); } } Between attempts to DataBind the GridView, I change the table's values expecting it to invalidate the Cache["Pets"] item, but it seems to stay in the Cache indefinitely.

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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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• How to map combinations of things to a relational database?

  - by Space_C0wb0y

  I have a table whose records represent certain objects. For the sake of simplicity I am going to assume that the table only has one row, and that is the unique ObjectId. Now I need a way to store combinations of objects from that table. The combinations have to be unique, but can be of arbitrary length. For example, if I have the ObjectIds 1,2,3,4 I want to store the following combinations: {1,2}, {1,3,4}, {2,4}, {1,2,3,4} The ordering is not necessary. My current implementation is to have a table Combinations that maps ObjectIds to CombinationIds. So every combination receives a unique Id: ObjectId | CombinationId ------------------------ 1 | 1 2 | 1 1 | 2 3 | 2 4 | 2 This is the mapping for the first two combinations of the example above. The problem is, that the query for finding the CombinationId of a specific Combination seems to be very complex. The two main usage scenarios for this table will be to iterate over all combinations, and the retrieve a specific combination. The table will be created once and never be updated. I am using SQLite through JDBC. Is there any simpler way or a best practice to implement such a mapping?

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• Why does Linq to Entities generate Left Outer Joins?

  - by DJCasey

  I was wondering if anyone knew why linq to entities always seems to generate left outer joins. I would understand it on an optional relationship but it doesn't make good sense when the relationship is mandatory. Does anyone have any idea how to make it generate inner joins instead?

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• 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

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• Creating a foreign key in MySQL produces error:

  - by SnOrfus

  I'm trying to create a foreign key on a table in MySQL and I'm getting a strange error that there seems to be little info about in any of my searches. I'm creating the key with this (emitted from mysql workbench 5.2): ALTER TABLE `db`.`appointment` ADD CONSTRAINT `FK_appointment_CancellationID` FOREIGN KEY (`CancellationID` ) REFERENCES `db`.`appointment_cancellation` (`ID` ) ON DELETE NO ACTION ON UPDATE NO ACTION , ADD INDEX `FK_appointment_CancellationID` (`CancellationID` ASC) ; at which point I get the error: ERROR 1452: Cannot add or update a child row: a foreign key constraint fails (alarmtekcore., CONSTRAINT FK_lead_appointment_CancellationID FOREIGN KEY (CancellationID) REFERENCES lead_appointment_cancellation (`) I've checked here but there's no data in the table.

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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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• MySQL: Count occurrences of known (or enumerated) distinct values

  - by Eilidh

  After looking at how to count the occurrences of distinct values in a field, I am wondering how to count the occurrences of each distinct value if the distinct values are known (or enumerated). For example, if I have a simple table - TrafficLight Colour ------------ ------ 1 Red 2 Amber 3 Red 4 Red 5 Green 6 Green where one column (in this case Colour) has known (or enumerated) distinct values, how could I return the count for each colour as a separate value, rather than as an array, as in the linked example. To return an array with a count of each colour (using the same method as in the linked example), the query would be something like SELECT Colour COUNT(*) AS ColourCount FROM TrafficLights GROUP BY Colour, and return an array - Colour ColourCount ------ ----------- Red 3 Amber 1 Green 2 What I would like to do is to return the count for each Colour AS a separate total (e.g. RedCount). How can I do this?

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• Use appsettings connectionstring instead of connectionStrings in web config for datacontext designer

  - by bmutch

  I need to use the appsettings/key for my connection string in a web project, and want to re-use this for my connectionstring in the datacontext designer, but it seems all I can use there is the web.config's connectionStrings, so I have to have my DB location in 2 places in the web.config, how can I force the designer (dbml) to use the appsettings instead?

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• Using sqlalchemy to query using multiple column where in clause

  - by crunkchitis

  I'm looking to execute this query using sqlalchemy. SELECT name, age, favorite_color, favorite_food FROM kindergarten_classroom WHERE (favorite_color, favorite_food) IN (('lavender','lentil soup'),('black','carrot juice')); I only want kids that like (lavender AND lentil soup) OR (black and carrot juice). This is similar, but doesn't get me all of the way there: Sqlalchemy in clause

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• IDENTITY_INSERT is set to off error

  - by kingrichard2005

  I have a MVC web application with a table in the model that I would like to add to. I have the primary key set along with the other data fields, but every time I try to add to the table, I get the following error: "Cannot insert explicit value for identity column in table 'TABLE_NAME' when IDENTITY_INSERT is set to OFF." I'm not sure why this problem is coming up, I have the primary key set as the identity and it is also set to auto increment in the Visual Studio table designer. Is there any way I can adjust the IDENTITY_INSERT parameter in the table designer in Visual Studio?? Or is there some other issue that might be causing this.

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• Extending Zend DB Table to include BETWEEN and LIMIT.

  - by davykiash

  Am looking for how I can extend the Zend_DB_Table below to accomodate a BETWEEN two dates syntax and LIMIT syntax My current construct is class Model_DbTable_Tablelist extends Zend_Db_Table_Abstract { protected $_name = 'mytable'; $select = $this->select() ->setIntegrityCheck(false) ->from('mytable', array('MyCol1', 'MyDate')); } I want it extended to be equivalent to the query below SELECT MyCol1,MyDate FROM mytable WHERE MyDate BETWEEN '2008-04-03' AND '2009-01-02' LIMIT 0,20 Any ideas?

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• MySQL query to order by parent then child places

  - by Swanny

  I have a table of pages in my database, each page can have a parent as below: id parent_id title 1 0 Home 2 0 Sitemap 3 0 Products 4 3 Product 1 5 3 Product 2 6 4 Product 1 Review Page What would be the best MySQL query to select all pages ordered by parent then child then child again if there is more than one level, there will be a maximum of three levels. The above example would produce the desired order: Home Sitemap Products Product 1 Product 1 Review Page Product 2

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• Select proper columns from JOIN statement

  - by Alexander Stalt

  I have two tables: table1, table2. Table1 has 10 columns, table2 has 2 columns. SELECT * FROM table1 AS T1 INNER JOIN table2 AS T2 ON T1.ID = T2.ID I want to select all columns from table1 and only 1 column from table2. Is it possible to do that without enumerating all columns from table1 ?

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• Array not showing in Jlist but filled in console

  - by OVERTONE

  Hey there. been a busy debugger today. ill give ths short version. ive made an array list that takes names from a database. then i put the contents of the arraylist into an array of strings. now i want too display the arrays contents in a JList. the weird thing is it was working earlier. and ive two methods. ones just a little practice too make sure i was adding to the Jlist correctly. so heres the key codes. this is the layout of my code. variables constructor methods in my variables i have these 3 defined String[] contactListNames = new String[5]; ArrayList<String> rowNames = new ArrayList<String>(); JList contactList = new JList(contactListNames); simple enough. in my constructor i have them again. contactListNames = new String[5]; contactList = new JList(contactListNames); //i dont have the array list defined though. printSqlDetails(); // the prinSqldetails was too make sure that the connectionw as alright. and its working fine. fillContactList(); // this is the one thats causing me grief. its where all the work happens. // fillContactListTest(); // this was the tester that makes sure its adding to the list alright. heres the code for fillContactListTest() public void fillContactListTest() { for(int i = 0;i<3;i++) { try { String contact; System.out.println(" please fill the list at index "+ i); Scanner in = new Scanner(System.in); contact = in.next(); contactListNames[i] = contact; in.nextLine(); } catch(Exception e) { e.printStackTrace(); } } } heres the main one thats supposed too work. public void fillContactList() { int i =0; createConnection(); ArrayList<String> rowNames = new ArrayList<String>(); try { Statement stmt = conn.createStatement(); ResultSet namesList = stmt.executeQuery("SELECT name FROM Users"); try { while (namesList.next()) { rowNames.add(namesList.getString(1)); contactListNames =(String[])rowNames.toArray(new String[rowNames.size()]); // this used to print out contents of array list // System.out.println("" + rowNames); while(i<contactListNames.length) { System.out.println(" " + contactListNames[i]); i++; } } } catch(SQLException q) { q.printStackTrace(); } conn.commit(); stmt.close(); conn.close(); } catch(SQLException e) { e.printStackTrace(); } } i really need help here. im at my wits end. i just cant see why the first method would add to the JList no problem. but the second one wont. both the contactListNames array and array list can print fine and have the names in them. but i must be transfering them too the jlist wrong. please help p.s im aware this is long. but trust me its the short version.

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