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• Adding a 2008 server to a 2003 Domain with DNS devolution?

  - by mvdwege

  I'm running into a problem adding a 2008 server to our existing 2003 domain, and as I am not a Windows admin, I'm not getting the problem here. Some reading around on Technet seems to indicate that DNS devolution is the issue. Here's the setup: DNS for the entire company is hosted on a Unix server running Bind, including the service records for the Windows domain. Our toplevel is company.local, and functional domains are in subdomains, such as mgt.company.local (our management servers). Our Windows servers live mostly in office.company.local, but some of them live in .mgt.company.local and .customers.company.local. The 2003 servers all succesfully authenticate against company.local as the Windows domain. Their position in the infrastructure is set by setting the primary DNS suffix under the network settings and the computer name dialog. Trying to do the same with a brand new 2008 install throws an error though: "Changing the Primary Domain DNS name of this computer to office.company.local failed [...] The specified server cannot perform the requested operation" I tried googling, but the closest I came was the Technet article on DNS Devolution, and I can't make heads nor tails on how to apply that to my case. Addendum 2012-10-23: The problem is not joining the domain, that works, the problem is that it joins with the wrong name, as .company.local, instead of .office.company.local. So far everything works, but I'm rather afraid to run production like this, because sooner or later something is going to complain about the AD name not matching DNS.

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• Hibernate Criteria: Perform JOIN in Subquery/DetachedCriteria

  - by Gilean

  I'm running into an issue with adding JOIN's to a subquery using DetachedCriteria. The code looks roughly like this: Criteria criteria = createCacheableCriteria(ProductLine.class, "productLine"); criteria.add(Expression.eq("productLine.active", "Y")); DetachedCriteria subCriteria = DetachedCriteria.forClass(Models.class, "model"); subCriteria.setProjection(Projections.rowCount()); subCriteria.createAlias("model.language", "modelLang"); criteria.add(Expression.eq("modelLang.language_code", "EN")); subCriteria.add(Restrictions.eqProperty("model.productLine.id","productLine.id")); criteria.add(Subqueries.lt(0, subCriteria)); But the logged SQL does not contain the JOIN in the subquery, but does include the alias which is throwing an error SELECT * FROM PRODUCT_LINES this_ WHERE this_.ACTIVE=? AND ? < (SELECT COUNT(*) AS y0_ FROM MODELS this0__ WHERE modelLang3_.LANGUAGE ='EN' AND this0__.PRODUCT_LINE_ID =this_.ID ) How can I add the joins to the DetachedCriteria? Hibernate version: 3.2.6.ga Hibernate core: 3.3.2.GA Hibernate annotations: 3.4.0.GA Hibernate commons-annotations: 3.3.0.ga Hibernate entitymanager: 3.4.0.GA Hibernate validator: 3.1.0.GA

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• Wordpress SQL Select Multiple Meta Values / Meta Keys / Custom Fields

  - by Wes

  I am trying to modify a wordpress / MySQL function to display a little more information. I'm currently running the following query that selects the post, joins the 'postmeta' and gets the info where the meta_key = _liked function most_liked_posts($numberOf, $before, $after, $show_count) { global $wpdb; $request = "SELECT ID, post_title, meta_value FROM $wpdb->posts, $wpdb->postmeta"; $request .= " WHERE $wpdb->posts.ID = $wpdb->postmeta.post_id"; $request .= " AND post_status='publish' AND post_type='post' AND meta_key='_liked' "; $request .= " ORDER BY $wpdb->postmeta.meta_value+0 DESC LIMIT $numberOf"; $posts = $wpdb->get_results($request); foreach ($posts as $post) { $post_title = stripslashes($post->post_title); $permalink = get_permalink($post->ID); $post_count = $post->meta_value; echo $before.'<a href="' . $permalink . '" title="' . $post_title.'" rel="nofollow">' . $post_title . '</a>'; echo $show_count == '1' ? ' ('.$post_count.')' : ''; echo $after; } } The important part being: $post_count = $post->meta_value; But now I want to also grab a value that is attached to each post called wbphoto How do I specify that $post_count = _liked and $photo = wbphoto ? Here is a screen cap of my Phpmyadmin

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• MS SQL 2008, join or no join?

  - by Patrick

  Just a small question regarding joins. I have a table with around 30 fields and i was thinking about making a second table to store 10 of those fields. Then i would just join them in with the main data. The 10 fields that i was planning to store in a second table does not get queried directly, it's just some settings for the data in the first table. Something like: Table 1 Id Data1 Data2 Data3 etc ... Table 2 Id (same id as table one) Settings1 Settings2 Settings3 Is this a bad solution? Should i just use 1 table? How much performance inpact does it have? All entries in table 1 would also then have an entry in table 2. Small update is in order. Most of the Data fields are of the type varchar and 2 of them are of the type text. How is indexing treated? My plan is to index 2 data fields, email (varchar 50) and author (varchar 20). And yes, all records in Table 1 will have a record in Table 2. Most of the settings fields are of the bit type, around 80%. The rest is a mix between int and varchar. The varchars can be null.

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• JPA Lookup Hierarchy Mapping

  - by Andy Trujillo

  Given a lookup table: | ID | TYPE | CODE | DESCRIPTION | | 1 | ORDER_STATUS | PENDING | PENDING DISPOSITION | | 2 | ORDER_STATUS | OPEN | AWAITING DISPOSITION | | 3 | OTHER_STATUS | OPEN | USED BY OTHER ENTITY | If I have an entity: @MappedSuperclass @Table(name="LOOKUP") @Inheritance(strategy=InheritanceType.SINGLE_TABLE) @DiscriminatorColumn(name="TYPE", discriminatorType=DiscriminatorType.STRING) public abstract class Lookup { @Id @Column(name="ID") int id; @Column(name="TYPE") String type; @Column(name="CODE") String code; @Column(name="DESC") String description; ... } Then a subclass: @Entity @DiscriminatorValue("ORDER_STATUS") public class OrderStatus extends Lookup { } The expectation is to map it: @Entity @Table(name="ORDERS") public class OrderVO { ... @ManyToOne @JoinColumn(name="STATUS", referencedColumnName="CODE") OrderStatus status; ... } So that the CODE is stored in the database. I expected that if I wrote: OrderVO o = entityManager.find(OrderVO.class, 123); the SQL generated using OpenJPA would look something like: SELECT t0.id, ..., t1.CODE, t1.TYPE, t1.DESC FROM ORDERS t0 LEFT OUTER JOIN LOOKUP t1 ON t0.STATUS = t1.CODE AND t1.TYPE = 'ORDER_STATUS' WHERE t0.ID = ? But the actual SQL that gets generated is missing the AND t1.TYPE = 'ORDER_STATUS' This causes a problem when the CODE is not unique. Is there a way to have the discriminator included on joins or am I doing something wrong here?

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• MySQL performance - 100Mb ethernet vs 1Gb ethernet

  - by Rob Penridge

  Hi All I've just started a new job and noticed that the analysts computers are connected to the network at 100Mbps. The ODBC queries we run against the MySQL server can easily return 500MB+ and it seems at times when the servers are under high load the DBAs kill low priority jobs as they are taking too long to run. My question is this... How much of this server time is spent executing the request, and how much time is spent returning the data to the client? Could the query speeds be improved by upgrading the network connections to 1Gbps? (Updated for the why): The database in question was built to accomodate reporting needs and contains massive amounts of data. We usually work with subsets of this data at a granular level in external applications such as SAS or Excel, hence the reason for the large amounts of data being transmitted. The queries are not poorly structured - they are very simple and the appropriate joins/indexes etc are being used. I've removed 'query' from the Title of the post as I realised this question is more to do with general MySQL performance rather than query related performance. I was kind of hoping that someone with a Gigabit connection may be able to actually quantify some results for me here by running a query that returns a decent amount of data, then they could limit their connection speed to 100Mb and rerun the same query. Hopefully this could be done in an environment where loads are reasonably stable so as not to skew the results. If ethernet speed can improve the situation I wanted some quantifiable results to help argue my case for upgrading the network connections. Thanks Rob

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• Select the latest record for each category linked available on an object

  - by Simpleton

  I have a tblMachineReports with the columns: Status(varchar),LogDate(datetime),Category(varchar), and MachineID(int). I want to retrieve the latest status update from each category for every machine, so in effect getting a snapshot of the latest statuses of all the machines unique to their MachineID. The table data would look like Category - Status - MachineID - LogDate cata - status1 - 001 - date1 cata - status2 - 002 - date2 catb - status3 - 001 - date2 catc - status2 - 002 - date4 cata - status3 - 001 - date5 catc - status1 - 001 - date6 catb - status2 - 001 - date7 cata - status2 - 002 - date8 catb - status2 - 002 - date9 catc - status2 - 001 - date10 Restated, I have multiple machines reporting on multiple statuses in this tblMachineReports. All the rows are created through inserts, so their will obviously be duplicate entries for machines as new statuses come in. None of the columns can be predicted, so I can't do any ='some hard coded string' comparisons in any part of the select statement. For the sample table I provided, the desired results would look like: Category - Status - MachineID - LogDate catc - status2 - 002 - date4 cata - status3 - 001 - date5 catb - status2 - 001 - date7 cata - status2 - 002 - date8 catb - status2 - 002 - date9 catc - status2 - 001 - date10 What would the select statement look like to achieve this, getting the latest status for each category on each machine, using MS SQL Server 2008? I have tried different combinations of subqueries combined with aggregate MAX(LogDates)'s, along with joins, group bys, distincts, and what-not, but have yet to find a working solution.

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• Legit? Two foreign keys referencing the same primary key.

  - by Ryan

  Hi All, I'm a web developer and have recently started a project with a company. Currently, I'm working with their DBA on getting the schema laid out for the site, and we've come to a disagreement regarding the design on a couple tables, and I'd like some opinions on the matter. Basically, we are working on a site that will implement a "friends" network. All users of the site will be contained in a table tblUsers with (PersonID int identity PK, etc). What I am wanting to do is to create a second table, tblNetwork, that will hold all of the relationships between users, with (NetworkID int identity PK, Owners_PersonID int FK, Friends_PersonID int FK, etc). Or conversely, remove the NetworkID, and have both the Owners_PersonID and Friends_PersonID shared as the Primary key. This is where the DBA has his problem. Saying that "he would only implement this kind of architecture in a data warehousing schema, and not for a website, and this is just another example of web developers trying to take the easy way out." Now obviously, his remark was a bit inflammatory, and that have helped motivate me to find an suitable answer, but more so, I'd just like to know how to do it right. I've been developing databases and programming for over 10 years, have worked with some top-notch minds, and have never heard this kind of argument. What the DBA is wanting to do is instead of storing both the Owners_PersonId and Friends_PersonId in the same table, is to create a third table tblFriends to store the Friends_PersonId, and have the tblNetwork have (NetworkID int identity PK, Owner_PersonID int FK, FriendsID int FK(from TBLFriends)). All that tblFriends would house would be (FriendsID int identity PK, Friends_PersonID(related back to Persons)). To me, creating the third table is just excessive in nature, and does nothing but create an alias for the Friends_PersonID, and cause me to have to add (what I view as unneeded) joins to all my queries, not to mention the extra cycles that will be necessary to perform the join on every query. Thanks for reading, appreciate comments. Ryan

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• SQL Server 2008, join or no join?

  - by Patrick

  Just a small question regarding joins. I have a table with around 30 fields and i was thinking about making a second table to store 10 of those fields. Then i would just join them in with the main data. The 10 fields that i was planning to store in a second table does not get queried directly, it's just some settings for the data in the first table. Something like: Table 1 Id Data1 Data2 Data3 etc ... Table 2 Id (same id as table one) Settings1 Settings2 Settings3 Is this a bad solution? Should i just use 1 table? How much performance inpact does it have? All entries in table 1 would also then have an entry in table 2. Small update is in order. Most of the Data fields are of the type varchar and 2 of them are of the type text. How is indexing treated? My plan is to index 2 data fields, email (varchar 50) and author (varchar 20). And yes, all records in Table 1 will have a record in Table 2. Most of the settings fields are of the bit type, around 80%. The rest is a mix between int and varchar. The varchars can be null.

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• Hibernate "JOIN ... ON"?

  - by CaptainAwesomePants

  I have an application that uses Hibernate for its domain objects. One part of the app is common between a few apps, and it has no knowledge of the other systems. In order to handle relations, our class looks like this: @Entity public class SystemEvent { @Id @GeneratedValue public int entity_id; @Column(name="event_type") public String eventType; @Column(name="related_id") public int relatedObjectId; } relatedObjectId holds a foreign key to one of several different objects, depending on the type of event. When a system wants to know about events that are relevant to its interests, it grabs all the system events with eventType "NewAccounts" or some such thing, and it knows that all of those relatedObjectIds are IDs to a "User" object or similar. Unfortunately, this has caused a problem down the line. I can't figure out a way to tell Hibernate about this mapping, which means that HQL queries can't do joins. I'd really like to create an HQL query that looks like this: SELECT users FROM SystemEvent event join Users newUsers where event.eventType = 'SignUp' However, Hibernate has no knowledge of the relationship between SystemEvent and Users, and as far as I can tell, there's no way to tell it. So here's my question: Is there any way to tell Hibernate about a relationship when your domain objects reference each other via ID numbers and not class references?

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• MySQL Unique hash insertion

  - by Jesse

  So, imagine a mysql table with a few simple columns, an auto increment, and a hash (varchar, UNIQUE). Is it possible to give mysql a query that will add a column, and generate a unique hash without multiple queries? Currently, the only way I can think of to achieve this is with a while, which I worry would become more and more processor intensive the more entries were in the db. Here's some pseudo-php, obviously untested, but gets the general idea across: while(!query("INSERT INTO table (hash) VALUES (".generate_hash().");")){ //found conflict, try again. } In the above example, the hash column would be UNIQUE, and so the query would fail. The problem is, say there's 500,000 entries in the db and I'm working off of a base36 hash generator, with 4 characters. The likelyhood of a conflict would be almost 1 in 3, and I definitely can't be running 160,000 queries. In fact, any more than 5 I would consider unacceptable. So, can I do this with pure SQL? I would need to generate a base62, 6 char string (like: "j8Du7X", chars a-z, A-Z, and 0-9), and either update the last_insert_id with it, or even better, generate it during the insert. I can handle basic CRUD with MySQL, but even JOINs are a little outside of my MySQL comfort zone, so excuse my ignorance if this is cake. Any ideas? I'd prefer to use either pure MySQL or PHP & MySQL, but hell, if another language can get this done cleanly, I'd build a script and AJAX it too. Thanks!

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• Querying a self referencing join with NHibernate Linq

  - by Ben

  In my application I have a Category domain object. Category has a property Parent (of type category). So in my NHibernate mapping I have: <many-to-one name="Parent" column="ParentID"/> Before I switched to NHibernate I had the ParentId property on my domain model (mapped to the corresponding database column). This made it easy to query for say all top level categories (ParentID = 0): where(c => c.ParentId == 0) However, I have since removed the ParentId property from my domain model (because of NHibernate) so I now have to do the same query (using NHibernate.Linq) like so: public IList<Category> GetCategories(int parentId) { if (parentId == 0) return _catalogRepository.Categories.Where(x => x.Parent == null).ToList(); else return _catalogRepository.Categories.Where(x => x.Parent.Id == parentId).ToList(); } The real impact that I can see, is the sql generated. Instead of a simple 'select x,y,z from categories where parentid = 0' NHibernate generates a left outer join: SELECT this_.CategoryId as CategoryId4_1_, this_.ParentID as ParentID4_1_, this_.Name as Name4_1_, this_.Slug as Slug4_1_, parent1_.CategoryId as CategoryId4_0_, parent1_.ParentID as ParentID4_0_, parent1_.Name as Name4_0_, parent1_.Slug as Slug4_0_ FROM Categories this_ left outer join Categories parent1_ on this_.ParentID = parent1_.CategoryId WHERE this_.ParentID is null Which doesn't seems much less efficient that what I had before. Is there a better way of querying these self referencing joins as it's very tempting to drop the ParentID back onto my domain model for this reason. Thanks, Ben

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• Java synchronized seems ignored

  - by viraptor

  Hi, I've got the following code, which I expected to deadlock after printing out "Main: pre-sync". But it looks like synchronized doesn't do what I expect it to. What happens here? import java.util.*; public class deadtest { public static class waiter implements Runnable { Object obj; public waiter(Object obj) { this.obj = obj; } public void run() { System.err.println("Thead: pre-sync"); synchronized(obj) { System.err.println("Thead: pre-wait"); try { obj.wait(); } catch (Exception e) { } System.err.println("Thead: post-wait"); } System.err.println("Thead: post-sync"); } } public static void main(String args[]) { Object obj = new Object(); System.err.println("Main: pre-spawn"); Thread waiterThread = new Thread(new waiter(obj)); waiterThread.start(); try { Thread.sleep(1000); } catch (Exception e) { } System.err.println("Main: pre-sync"); synchronized(obj) { System.err.println("Main: pre-notify"); obj.notify(); System.err.println("Main: post-notify"); } System.err.println("Main: post-sync"); try { waiterThread.join(); } catch (Exception e) { } } } Since both threads synchronize on the created object, I expected the threads to actually block each other. Currently, the code happily notifies the other thread, joins and exits.

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• What is your best-practice advice on implementing SQL stored procedures (in a C# winforms applicatio

  - by JYelton

  I have read these very good questions on SO about SQL stored procedures: When should you use stored procedures? and Are Stored Procedures more efficient, in general, than inline statements on modern RDBMS’s? I am a beginner on integrating .NET/SQL though I have used basic SQL functionality for more than a decade in other environments. It's time to advance with regards to organization and deployment. I am using .NET C# 3.5, Visual Studio 2008 and SQL Server 2008; though this question can be regarded as language- and database- agnostic, meaning that it could easily apply to other environments that use stored procedures and a relational database. Given that I have an application with inline SQL queries, and I am interested in converting to stored procedures for organizational and performance purposes, what are your recommendations for doing so? Here are some additional questions in my mind related to this subject that may help shape the answers: Should I create the stored procedures in SQL using SQL Management Studio and simply re-create the database when it is installed for a client? Am I better off creating all of the stored procedures in my application, inside of a database initialization method? It seems logical to assume that creating stored procedures must follow the creation of tables in a new installation. My database initialization method creates new tables and inserts some default data. My plan is to create stored procedures following that step, but I am beginning to think there might be a better way to set up a database from scratch (such as in the installer of the program). Thoughts on this are appreciated. I have a variety of queries throughout the application. Some queries are incredibly simple (SELECT id FROM table) and others are extremely long and complex, performing several joins and accepting approximately 80 parameters. Should I replace all queries with stored procedures, or only those that might benefit from doing so? Finally, as this topic obviously requires some research and education, can you recommend an article, book, or tutorial that covers the nuances of using stored procedures instead of direct statements?

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• JPA ManyToMany referencing issue

  - by dharga

  I have three tables. AvailableOptions and PlanTypeRef with a ManyToMany association table called AvailOptionPlanTypeAssoc. The trimmed down schemas look like this CREATE TABLE [dbo].[AvailableOptions]( [SourceApplication] [char](8) NOT NULL, [OptionId] [int] IDENTITY(1,1) NOT NULL, ... ) CREATE TABLE [dbo].[AvailOptionPlanTypeAssoc]( [SourceApplication] [char](8) NOT NULL, [OptionId] [int] NOT NULL, [PlanTypeCd] [char](2) NOT NULL, ) CREATE TABLE [dbo].[PlanTypeRef]( [PlanTypeCd] [char](2) NOT NULL, [PlanTypeDesc] [varchar](32) NOT NULL, ) And the Java code looks like this. //AvailableOption.java @ManyToMany(cascade={CascadeType.ALL}, fetch=FetchType.EAGER) @JoinTable( name = "AvailOptionPlanTypeAssoc", joinColumns = { @JoinColumn(name = "OptionId"), @JoinColumn(name="SourceApplication")}, inverseJoinColumns=@JoinColumn(name="PlanTypeCd")) List<PlanType> planTypes = new ArrayList<PlanType>(); //PlanType.java @ManyToMany @JoinTable( name = "AvailOptionPlanTypeAssoc", joinColumns = { @JoinColumn(name = "PlanTypeCd")}, inverseJoinColumns={@JoinColumn(name="OptionId"), @JoinColumn(name="SourceApplication")}) List<AvailableOption> options = new ArrayList<AvailableOption>(); The problem arises when making a select on AvailableOptions it joins back onto itself. Note the following SQL code from the backtrace. The second inner join should be on PlanTypeRef. SELECT t0.OptionId, t0.SourceApplication, t2.PlanTypeCd, t2.EffectiveDate, t2.PlanTypeDesc, t2.SysLstTrxDtm, t2.SysLstUpdtUserId, t2.TermDate FROM dbo.AvailableOptions t0 INNER JOIN dbo.AvailOptionPlanTypeAssoc t1 ON t0.OptionId = t1.OptionId AND t0.SourceApplication = t1.SourceApplication INNER JOIN dbo.AvailableOptions t2 ON t1.PlanTypeCd = t2.PlanTypeCd WHERE (t0.SourceApplication = ? AND t0.OptionType = ?) ORDER BY t0.OptionId ASC, t0.SourceApplication ASC [params=(String) testApp, (String) junit0]}

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• Using Oracle hint "FIRST_ROWS" to improve Oracle database performances

  - by bobetko

  I have a statement that runs on Oracle database server. The statement has about 5 joins and there is nothing unusual there. It looks pretty much like below: SELECT field1, field2, field3, ... FROM table1, table2, table3, table4, table5 WHERE table1.id = table2.id AND table2.id = table3.id AND ... table5.userid = 1 The problem (and what is interesting) is that statement for userid = 1 takes 1 second to return 590 records. Statement for userid = 2 takes around 30 seconds to return 70 records. I don't understand why is difference so big. It seems that different execution plan is chosen for statement with userid = 1 and different for userid = 2. After I implemented Oracle Hint FIRST_ROW, performance become significantly better. Both statements (for both ids 1 and 2) produce return in under 1 second. SELECT /*+ FIRST_ROWS */ field1, field2, field3, ... FROM table1, table2, table3, table4, table5 WHERE table1.id = table2.id AND table2.id = table3.id AND ... table5.userid = 1 Questions: 1) What are possible reasons for bad performance when userid = 2 (when hint is not used)? 2) Why would execution plan be different for one vs another statement (when hint is not used)? 3) Is there anything that I should be careful about when deciding to add this hint to my queries? Thanks

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• SQL 2005 indexed queries slower than unindexed queries

  - by uos??

  Adding a seemingly perfectly index is having an unexpectedly adverse affect on a query performance... -- [Data] has a predictable structure and a simple clustered index of the primary key: ALTER TABLE [dbo].[Data] ADD PRIMARY KEY CLUSTERED ( [ID] ) -- My query, joins on itself looking for a certain kind of "overlapping" records SELECT DISTINCT [Data].ID AS [ID] FROM dbo.[Data] AS [Data] JOIN dbo.[Data] AS [Compared] ON [Data].[A] = [Compared].[A] AND [Data].[B] = [Compared].[B] AND [Data].[C] = [Compared].[C] AND ([Data].[D] = [Compared].[D] OR [Data].[E] = [Compared].[E]) AND [Data].[F] <> [Compared].[F] WHERE 1=1 AND [Data].[A] = @A AND @CS <= [Data].[C] AND [Data].[C] < @CE -- Between a range [Data] has about a quarter-million records so far, 10% to 50% of the data satisfies the where clause depending on @A, @CS, and @CE. As is, the query takes 1 second to return about 300 rows when querying 10%, and 30 seconds to return 3000 rows when querying 50% of the data. Curiously, the estimated/actual execution plan indicates two parallel Clustered Index Scans, but the clustered index is only of the ID, which isn't part of the conditions of the query, only the output. ?? If I add this hand-crafted [IDX_A_B_C_D_E_F] index which I fully expected to improve performance, the query slows down by a factor of 8 (8 seconds for 10% & 4 minutes for 50%). The estimated/actual execution plans show an Index Seek, which seems like the right thing to be doing, but why so slow?? CREATE UNIQUE INDEX [IDX_A_B_C_D_E_F] ON [dbo].[Data] ([A], [B], [C], [D], [E], [F]) INCLUDE ([ID], [X], [Y], [Z]); The Data Engine Tuning wizard suggests a similar index with no noticeable difference in performance from this one. Moving AND [Data].[F] <> [Compared].[F] from the join condition to the where clause makes no difference in performance. I need these and other indexes for other queries. I'm sure I could hint that the query should refer to the Clustered Index, since that's currently winning - but we all know it is not as optimized as it could be, and without a proper index, I can expect the performance will get much worse with additional data. What gives?

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• should this database table be normalized?

  - by oo

  i have taken over a database that stores fitness information and we were having a debate about a certain table and whether it should stay as one table or get broken up into three tables. Today, there is one table called: workouts that has the following fields id, exercise_id, reps, weight, date, person_id So if i did 2 sets of 3 different exercises on one day, i would have 6 records in that table for that day. for example: id, exercise_id, reps, weight, date, person_id 1, 1, 10, 100, 1/1/2010, 10 2, 1, 10, 100, 1/1/2010, 10 3, 1, 10, 100, 1/1/2010, 10 4, 2, 10, 100, 1/1/2010, 10 5, 2, 10, 100, 1/1/2010, 10 6, 2, 10, 100, 1/1/2010, 10 So the question is, given that there is some redundant data (date, personid, exercise_id) in multiple records, should this be normalized to three tables WorkoutSummary: - id - date - person_id WorkoutExercise: - id - workout_id (foreign key into WorkoutSummary) - exercise_id WorkoutSets: - id - workout_exercise_id (foreign key into WorkoutExercise) - reps - weight I would guess the downside is that the queries would be slower after this refactoring as now we would need to join 3 tables to do the same query that had no joins before. The benefit of the refactoring allows up in the future to add new fields at the workout summary level or the exercise level with out adding in more duplication. any feedback on this debate?

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• refactor LINQ TO SQL custom properties that instantiate datacontext

  - by Thiago Silva

  I am working on an existing ASP.NET MVC app that started small and has grown with time to require a good re-architecture and refactoring. One thing that I am struggling with is that we've got partial classes of the L2S entities so we could add some extra properties, but these props create a new data context and query the DB for a subset of data. This would be the equivalent to doing the following in SQL, which is not a very good way to write this query as oppsed to joins: SELECT tbl1.stuff, (SELECT nestedValue FROM tbl2 WHERE tbl2.Foo = tbl1.Bar), tbl1.moreStuff FROM tbl1 so in short here's what we've got in some of our partial entity classes: public partial class Ticket { public StatusUpdate LastStatusUpdate { get { //this static method call returns a new DataContext but needs to be refactored var ctx = OurDataContext.GetContext(); var su = Compiled_Query_GetLastUpdate(ctx, this.TicketId); return su; } } } We've got some functions that create a compiled query, but the issue is that we also have some DataLoadOptions defined in the DataContext, and because we instantiate a new datacontext for getting these nested property, we get an exception "Compiled Queries across DataContexts with different LoadOptions not supported" . The first DataContext is coming from a DataContextFactory that we implemented with the refactorings, but this second one is just hanging off the entity property getter. We're implementing the Repository pattern in the refactoring process, so we must stop doing stuff like the above. Does anyone know of a good way to address this issue?

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• how to write this typical mysql query( ho to use subquery column into main query)

  - by I Like PHP

  I HAVE TWO TABLES shown below table_joining id join_id(PK) transfer_id(FK) unit_id transfer_date joining_date 1 j_1 t_1 u_1 2010-06-05 2010-03-05 2 j_2 t_2 u_3 2010-05-10 2010-03-10 3 j_3 t_3 u_6 2010-04-10 2010-01-01 4 j_5 NULL u_3 NULL 2010-06-05 5 j_6 NULL u_4 NULL 2010-05-05 table_transfer id transfer_id(PK) pastUnitId futureUnitId effective_transfer_date 1 t_1 u_3 u_1 2010-06-05 2 t_2 u_6 u_1 2010-05-10 3 t_3 u_5 u_3 2010-04-10 now i want to know total employee detalis( using join_id) which are currently working on unit u_3 . means i want only join_id j_1 (has transfered but effective_transfer_date is future date, right now in u_3) j_2 ( tansfered and right now in `u_3` bcoz effective_transfer_date has been passed) j_6 ( right now in `u_3` and never transfered) what i need to take care of below steps( as far as i know ) <1> first need to check from table_joining whether transfer_id is NULL or not <2> if transfer_id= is NULL then see unit_id=u_3 where joining_date <=CURDATE() ( means that person already joined u_3) <3> if transfer_id is NOT NULL then go to table_transfer using transfer_id (foreign key reference) <4> now see the effective_transfer_date regrading that transfer_id whether effective_transfer_date<=CURDATE() <5> if transfer date has been passed(means transfer has been done) then return futureUnitID otherwise return pastUnitID i used two separate query but don't know how to join those query?? for step <1 ans <2 SELECT unit_id FROM table_joining WHERE joining_date<=CURDATE() AND transfer_id IS NULL AND unit_id='u_3' for step<5 SELECT IF(effective_transfer_date <= CURDATE(),futureUnitId,pastUnitId) AS currentUnitID FROM table_transfer // here how do we select only those rows which have currentUnitID='u_3' ?? please guide me the process?? i m just confused with JOINS. i think using LEFT JOIN can return the data i need, but i m not getting how to implement ...please help me. Thanks for helping me alwayz

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• Should we have a database independent SQL like query language in Django? [closed]

  - by Yugal Jindle

  Note : I know we have Django ORM already that keeps things database independent and converts to the database specific SQL queries. Once things starts getting complicated it is preferred to write raw SQL queries for better efficiency. When you write raw sql queries your code gets trapped with the database you are using. I also understand its important to use the full power of your database that can-not be achieved with the django orm alone. My Question : Until I use any database specific feature, why should one be trapped with the database. For instance : We have a query with multiple joins and we decided to write a raw sql query. Now, that makes my website postgres specific. Even when I have not used any postgres specific feature. I feel there should be some fake sql language which can translate to any database's sql query. Even Django's ORM can be built over it. So, that if you go out of ORM but not database specific - you can still remain database independent. I asked the same question to Jacob Kaplan Moss (In person) : He advised me to stay with the database that I like and endure its whole power, to which I agree. But my point was not that we should be database independent. My point is we should be database independent until we use a database specific feature. Please explain, why should be there a fake sql layer over the actual sql ?

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• Optimize an SQL statement

  - by kovshenin

  Hey, I'm running WordPress, the database diagram could be found here: http://codex.wordpress.org/Database_Description After doing tonnes of filters and applying some hooks to the core, I'm left with the following query: SELECT SQL_CALC_FOUND_ROWS wp_posts.* FROM wp_posts JOIN wp_postmeta ppmeta_beds ON (ppmeta_beds.post_id = wp_posts.ID AND ppmeta_beds.meta_key = 'pp-general-beds' AND ppmeta_beds.meta_value >= 2) JOIN wp_postmeta ppmeta_baths ON (ppmeta_baths.post_id = wp_posts.ID AND ppmeta_baths.meta_key = 'pp-general-baths' AND ppmeta_baths.meta_value >= 3) JOIN wp_postmeta ppmeta_furnished ON (ppmeta_furnished.post_id = wp_posts.ID AND ppmeta_furnished.meta_key = 'pp-general-furnished' AND ppmeta_furnished.meta_value = 'yes') JOIN wp_postmeta ppmeta_pool ON (ppmeta_pool.post_id = wp_posts.ID AND ppmeta_pool.meta_key = 'pp-facilities-pool' AND ppmeta_pool.meta_value = 'yes') JOIN wp_postmeta ppmeta_pool_type ON (ppmeta_pool_type.post_id = wp_posts.ID AND ppmeta_pool_type.meta_key = 'pp-facilities-pool-type' AND ppmeta_pool_type.meta_value IN ('tennis', 'voleyball', 'basketball', 'fitness')) JOIN wp_postmeta ppmeta_sport ON (ppmeta_sport.post_id = wp_posts.ID AND ppmeta_sport.meta_key = 'pp-facilities-sport' AND ppmeta_sport.meta_value = 'yes') JOIN wp_postmeta ppmeta_sport_type ON (ppmeta_sport_type.post_id = wp_posts.ID AND ppmeta_sport_type.meta_key = 'pp-facilities-sport-type' AND ppmeta_sport_type.meta_value IN ('tennis', 'voleyball', 'basketball', 'fitness')) JOIN wp_postmeta ppmeta_parking ON (ppmeta_parking.post_id = wp_posts.ID AND ppmeta_parking.meta_key = 'pp-facilities-parking' AND ppmeta_parking.meta_value = 'yes') JOIN wp_postmeta ppmeta_parking_type ON (ppmeta_parking_type.post_id = wp_posts.ID AND ppmeta_parking_type.meta_key = 'pp-facilities-parking-type' AND ppmeta_parking_type.meta_value IN ('street', 'off-street', 'garage')) JOIN wp_postmeta ppmeta_garden ON (ppmeta_garden.post_id = wp_posts.ID AND ppmeta_garden.meta_key = 'pp-facilities-garden' AND ppmeta_garden.meta_value = 'yes') JOIN wp_postmeta ppmeta_garden_type ON (ppmeta_garden_type.post_id = wp_posts.ID AND ppmeta_garden_type.meta_key = 'pp-facilities-garden-type' AND ppmeta_garden_type.meta_value IN ('private', 'communal')) JOIN wp_postmeta ppmeta_type ON (ppmeta_type.post_id = wp_posts.ID AND ppmeta_type.meta_key = 'pp-general-type' AND ppmeta_type.meta_value IN ('villa', 'apartment', 'penthouse')) JOIN wp_postmeta ppmeta_status ON (ppmeta_status.post_id = wp_posts.ID AND ppmeta_status.meta_key = 'pp-general-status' AND ppmeta_status.meta_value IN ('off-plan', 'resale')) JOIN wp_postmeta ppmeta_location_type ON (ppmeta_location_type.post_id = wp_posts.ID AND ppmeta_location_type.meta_key = 'pp-location-type' AND ppmeta_location_type.meta_value IN ('beachfront', 'countryside', 'town-center', 'near-the-sea', 'hillside', 'private-resort')) JOIN wp_postmeta ppmeta_price_range ON (ppmeta_price_range.post_id = wp_posts.ID AND ppmeta_price_range.meta_key = 'pp-general-price' AND ppmeta_price_range.meta_value BETWEEN 10000 AND 50000) JOIN wp_postmeta ppmeta_area_range ON (ppmeta_area_range.post_id = wp_posts.ID AND ppmeta_area_range.meta_key = 'pp-general-area' AND ppmeta_area_range.meta_value BETWEEN 50 AND 150) WHERE 1=1 AND (((wp_posts.post_title LIKE '%fdsfsad%') OR (wp_posts.post_content LIKE '%fdsfsad%'))) AND wp_posts.post_type = 'property' AND (wp_posts.post_status = 'publish' OR wp_posts.post_status = 'private') ORDER BY wp_posts.post_date DESC LIMIT 0, 10 It's way too big. Could anybody please show me a way of optimizing all those joins into fewer statements? As you can see they all use the same tables but under different names. I'm not an SQL guru but I think there should be a way, because this is insane ;) Thanks! Update Here's what explain returns: http://twitpic.com/1cd36p

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• Using a custom IList obtained through NHibernate

  - by Abu Dhabi

  Hi.I'm trying to write a web page in .NET, using C# and NHibernate 2.1. The pertinent code looks like this: var whatevervar = session.CreateSQLQuery("select thread_topic, post_time, user_display_name, user_signature, user_avatar, post_topic, post_body from THREAD, [USER], POST, THREADPOST where THREADPOST.thread_id=" + id + " and THREADPOST.thread_id=THREAD.thread_id and [USER].user_id=POST.user_id and POST.post_id=THREADPOST.post_id ORDER BY post_time;").List(); (I have tried to use joins in HQL, but then fell back on this query, due to HQL's unreadability.) The problem is that I'm getting a result that is incompatible with a repeater. When I try this: posts.DataSource = whatevervar.; posts.DataBind(); ...I get this: DataBinding: 'System.Object[]' does not contain a property with the name 'user_avatar'. In an earlier project, I used LINQ to SQL for this same purpose, and it looked like so: var whatevervar = from threads in context.THREADs join threadposts in context.THREADPOSTs on threads.thread_id equals threadposts.thread_id join posts1 in context.POSTs on threadposts.post_id equals posts1.post_id join users in context.USERs on posts1.user_id equals users.user_id orderby posts1.post_time where threads.thread_id == int.Parse(id) select new { threads.thread_topic, posts1.post_time, users.user_display_name, users.user_signature, users.user_avatar, posts1.post_body, posts1.post_topic }; That worked, and now I want to do the same with NHibernate. Unfortunately, I don't know how to make the repeater recognize the fields of the result of the query. Thanks in advance!

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• How do you think while formulating Sql Queries. Is it an experience or a concept ?

  - by Shantanu Gupta

  I have been working on sql server and front end coding and have usually faced problem formulating queries. I do understand most of the concepts of sql that are needed in formulating queries but whenever some new functionality comes into the picture that can be dont using sql query, i do usually fails resolving them. I am very comfortable with select queries using joins and all such things but when it comes to DML operation i usually fails For every query that i never done before I usually finds uncomfortable with that while creating them. Whenever I goes for an interview I usually faces this problem. Is it their some concept behind approaching on formulating sql queries. Eg. I need to create an sql query such that A table contain single column having duplicate record. I need to remove duplicate records. I know i can find the solution to this query very easily on Googling, but I want to know how everyone comes to the desired result. Is it something like Practice Makes Man Perfect i.e. once you did it, next time you will be able to formulate or their is some logic or concept behind. I could have get my answer of solving above problem simply by posting it on stackoverflow and i would have been with an answer within 5 to 10 minutes but I want to know the reason. How do you work on any new kind of query. Is it a major contribution of experience or some an implementation of concepts. Whenever I learns some new thing in coding section I tries to utilize it wherever I can use it. But here scenario seems to be changed because might be i am lagging in some concepts.

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• How will Arel affect rails' includes() 's capabilities.

  - by Tim Snowhite

  I've looked over the Arel sources, and some of the activerecord sources for Rails 3.0, but I can't seem to glean a good answer for myself as to whether Arel will be changing our ability to use includes(), when constructing queries, for the better. There are instances when one might want to modify the conditions on an activerecord :include query in 2.3.5 and before, for the association records which would be returned. But as far as I know, this is not programmatically tenable for all :include queries: (I know some AR-find-includes make t#{n}.c#{m} renames for all the attributes, and one could conceivably add conditions to these queries to limit the joined sets' results; but others do n_joins + 1 number of queries over the id sets iteratively, and I'm not sure how one might hack AR to edit these iterated queries.) Will Arel allow us to construct ActiveRecord queries which specify the resulting associated model objects when using includes()? Ex: User :has_many posts( has_many :comments) User.all(:include => :posts) #say I wanted the post objects to have their #comment counts loaded without adding a comment_count column to `posts`. #At the post level, one could do so by: posts_with_counts = Post.all(:select => 'posts.*, count(comments.id) as comment_count', :joins => 'left outer join comments on comments.post_id = posts.id', :group_by => 'posts.id') #i believe #But it seems impossible to do so while linking these post objects to each #user as well, without running User.all() and then zippering the objects into #some other collection (ugly) #OR running posts.group_by(&:user) (even uglier, with the n user queries)

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