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  • postgres SQL - pg_class question

    - by Sachin Chourasiya
    PostgreSQL stores statistics about tables in the system table called pg_class. The query planner accesses this table for every query. These statistics may only be updated using the analyze command. If the analyze command is not run often, the statistics in this table may not be accurate and the query planner may make poor decisions which can degrade system performance. Another strategy is for the query planner to generate these statistics for each query (including selects, inserts, updates, and deletes). This approach would allow the query planner to have the most up-to-date statistics possible. Why postgres always rely on pg_class instead?

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  • Filtering with joined tables

    - by viraptor
    I'm trying to get some query performance improved, but the generated query does not look the way I expect it to. The results are retrieved using: query = session.query(SomeModel). options(joinedload_all('foo.bar')). options(joinedload_all('foo.baz')). options(joinedload('quux.other')) What I want to do is filter on the table joined via 'first', but this way doesn't work: query = query.filter(FooModel.address == '1.2.3.4') It results in a clause like this attached to the query: WHERE foos.address = '1.2.3.4' Which doesn't do the filtering in a proper way, since the generated joins attach tables foos_1 and foos_2. If I try that query manually but change the filtering clause to: WHERE foos_1.address = '1.2.3.4' AND foos_2.address = '1.2.3.4' It works fine. The question is of course - how can I achieve this with sqlalchemy itself?

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  • 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.

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  • Efficiently retrieve objects with one to many references in Grails using GORM

    - by bebeastie
    I'm trying to determine how to find/retrieve/load objects efficiently in terms of a.) minimizing calls to database and b.) keeping the code as elegant/simple as possible (i.e. not writing hql etc.). Assume you have two objects: public class Foo { Bar bar String badge } public class Bar { String name } Each Foo has a bar and a badge. Also assume that all badges are unique within a bar. So if a Foo has a badge "4565" there are no other Foos that have the same badge # AND the same bar. If I have a bar ID, how can I efficiently retrive the Foo w/o first selecting Bar? I know I can do this: Foo.findByBadgeAndBar("4565", Bar.findById("1")) But that seems to cause a select on the Bar table followed by a select on the Foo table. In other words, I need to produce the Grails/Hibernate/GORM equivalent of the following: select * from foo where badge="4565" and bar_id="1"

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  • Improving performance in this query

    - by Luiz Gustavo F. Gama
    I have 3 tables with user logins: sis_login = administrators tb_rb_estrutura = coordinators tb_usuario = clients I created a VIEW to unite all these users by separating them by levels, as follows: create view `login_names` as select `n1`.`cod_login` as `id`, '1' as `level`, `n1`.`nom_user` as `name` from `dados`.`sis_login` `n1` union all select `n2`.`id` as `id`, '2' as `level`, `n2`.`nom_funcionario` as `name` from `tb_rb_estrutura` `n2` union all select `n3`.`cod_usuario` as `id`, '3' as `level`, `n3`.`dsc_nome` as `name` from `tb_usuario` `n3`; So, can occur up to three ids repeated for different users, which is why I separated by levels. This VIEW is just to return me user name, according to his id and level. considering it has about 500,000 registered users, this view takes about 1 second to load. too much time, but is becomes very small when I need to return the latest posts on the forum of my website. The tables of the forums return the user id and level, then look for a name in this VIEW. I have registered 18 forums. When I run the query, it takes one second for each forum = 18 seconds. OMG. This page loads every time somebody enter my website. This is my query: select `x`.`forum_id`, `x`.`topic_id`, `l`.`nome` from ( select `t`.`forum_id`, `t`.`topic_id`, `t`.`data`, `t`.`user_id`, `t`.`user_level` from `tb_forum_topics` `t` union all select `a`.`forum_id`, `a`.`topic_id`, `a`.`data`, `a`.`user_id`, `a`.`user_level` from `tb_forum_answers` `a` ) `x` left outer join `login_names` `l` on `l`.`id` = `x`.`user_id` and `l`.`level` = `x`.`user_level` group by `x`.`forum_id` asc USING EXPLAIN: id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY <derived2> ALL NULL NULL NULL NULL 6 Using temporary; Using filesort 1 PRIMARY <derived4> ALL NULL NULL NULL NULL 530415 4 DERIVED n1 ALL NULL NULL NULL NULL 114 5 UNION n2 ALL NULL NULL NULL NULL 2 6 UNION n3 ALL NULL NULL NULL NULL 530299 NULL UNION RESULT ALL NULL NULL NULL NULL NULL 2 DERIVED t ALL NULL NULL NULL NULL 3 3 UNION r ALL NULL NULL NULL NULL 3 NULL UNION RESULT ALL NULL NULL NULL NULL NULL Somebody can help me or give a suggestion?

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  • Copying 6000 tables and data from sqlserver to oracle ==> fastest method?

    - by nazer555
    i need to copy the tables and data (about 5 yrs data, 6200 tables) stored in sqlserver, i am using datastage and odbc connection to connect and datstage automatically creates the table with data, but its taking 2-3 hours per table as tables are very large(0.5 gig, 300+columns and about 400k rows). How can i achieve this the fastes as at this rate i am able to only copy 5 tables per day but within 30 days i need move over these 6000 tables.

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  • how to Solve the "Digg" problem in MongoDB

    - by user193116
    A while back,a Digg developer had posted this blog ,"http://about.digg.com/blog/looking-future-cassandra", where the he described one of the issues that were not optimally solved in MySQL. This was cited as one of the reasons for their move to Cassandra. I have been playing with MongoDB and I would like to understand how to implement the MongoDB collections for this problem From the article, the schema for this information in MySQL : CREATE TABLE Diggs ( id INT(11), itemid INT(11), userid INT(11), digdate DATETIME, PRIMARY KEY (id), KEY user (userid), KEY item (itemid) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; CREATE TABLE Friends ( id INT(10) AUTO_INCREMENT, userid INT(10), username VARCHAR(15), friendid INT(10), friendname VARCHAR(15), mutual TINYINT(1), date_created DATETIME, PRIMARY KEY (id), UNIQUE KEY Friend_unique (userid,friendid), KEY Friend_friend (friendid) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; This problem is ubiquitous in social networking scenario implementation. People befriend a lot of people and they in turn digg a lot of things. Quickly showing a user what his/her friends are up to is very critical. I understand that several blogs have since then provided a pure RDBMs solution with indexes for this issue; however I am curious as to how this could be solved in MongoDB.

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  • How to run an .exe application in another computer?

    - by ADAM
    I am working on a C# application in Visual Studio 2013. When I run the .exe file from my computer, the application runs very well and all the features work. When I tried to run the .exe on another computer, the database side doesn't work well and the connection with the database couldn't be opened. The SqlConnection is constructed as follows: SqlConnection cn = new SqlConnection("Data Source=ADAM-PC;Initial Catalog=integrationdatabase;Integrated Security=True" I don't know how to change the data source to make the connection with the database established in another computer. How can I solve this problem?

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  • How to display MySQL Select statement results in PHP

    - by Vafello
    I have the following code and it should return just one value (id) from mysql table. The following code doesnt work. How can I output it without creating arrays and all this stuff, just a simple output of one value. $query = "SELECT id FROM users_entity WHERE username = 'Admin' "; $result = map_query($query); echo $result;

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  • Multi-tier applications using L2S, WCF and Base Class

    - by Gena Verdel
    Hi all. One day I decided to build this nice multi-tier application using L2S and WCF. The simplified model is : DataBase-L2S-Wrapper(DTO)-Client Application. The communication between Client and Database is achieved by using Data Transfer Objects which contain entity objects as their properties. abstract public class BaseObject { public virtual IccSystem.iccObjectTypes ObjectICC_Type { get { return IccSystem.iccObjectTypes.unknownType; } } [global::System.Data.Linq.Mapping.ColumnAttribute(Storage = "_ID", AutoSync = AutoSync.OnInsert, DbType = "BigInt NOT NULL IDENTITY", IsPrimaryKey = true, IsDbGenerated = true)] [global::System.Runtime.Serialization.DataMemberAttribute(Order = 1)] public virtual long ID { //get; //set; get { return _ID; } set { _ID = value; } } } [DataContract] public class BaseObjectWrapper<T> where T : BaseObject { #region Fields private T _DBObject; #endregion #region Properties [DataMember] public T Entity { get { return _DBObject; } set { _DBObject = value; } } #endregion } Pretty simple, isn't it?. Here's the catch. Each one of the mapped classes contains ID property itself so I decided to override it like this [global::System.Data.Linq.Mapping.TableAttribute(Name="dbo.Divisions")] [global::System.Runtime.Serialization.DataContractAttribute()] public partial class Division : INotifyPropertyChanging, INotifyPropertyChanged { [global::System.Data.Linq.Mapping.ColumnAttribute(Storage="_ID", AutoSync=AutoSync.OnInsert, DbType="BigInt NOT NULL IDENTITY", IsPrimaryKey=true, IsDbGenerated=true)] [global::System.Runtime.Serialization.DataMemberAttribute(Order=1)] public override long ID { get { return this._ID; } set { if ((this._ID != value)) { this.OnIDChanging(value); this.SendPropertyChanging(); this._ID = value; this.SendPropertyChanged("ID"); this.OnIDChanged(); } } } } Wrapper for division is pretty straightforward as well: public class DivisionWrapper : BaseObjectWrapper<Division> { } It worked pretty well as long as I kept ID values at mapped class and its BaseObject class the same(that's not very good approach, I know, but still) but then this happened: private CentralDC _dc; public bool UpdateDivision(ref DivisionWrapper division) { DivisionWrapper tempWrapper = division; if (division.Entity == null) { return false; } try { Table<Division> table = _dc.Divisions; var q = table.Where(o => o.ID == tempWrapper.Entity.ID); if (q.Count() == 0) { division.Entity._errorMessage = "Unable to locate entity with id " + division.Entity.ID.ToString(); return false; } var realEntity = q.First(); realEntity = division.Entity; _dc.SubmitChanges(); return true; } catch (Exception ex) { division.Entity._errorMessage = ex.Message; return false; } } When trying to enumerate over the in-memory query the following exception occurred: Class member BaseObject.ID is unmapped. Although I'm stating the type and overriding the ID property L2S fails to work. Any suggestions?

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  • Forum board example schema in YAML format - modify for Nested set?

    - by takeshin
    I have created a forum board app, based on YAML schema found in 'real world examples' of Doctrine Manual, which looks similar to this: --- Forum_Category: columns: root_category_id: integer(10) parent_category_id: integer(10) name: string(50) description: string(99999) relations: Subcategory: class: Forum_Category local: parent_category_id foreign: id Rootcategory: class: Forum_Category local: root_category_id foreign: id Forum_Board: columns: category_id: integer(10) name: string(100) description: string(5000) relations: Category: class: Forum_Category local: category_id foreign: id Threads: class: Forum_Thread local: id foreign: board_id Forum_Entry: columns: author: string(50) topic: string(100) message: string(99999) parent_entry_id: integer(10) thread_id: integer(10) date: integer(10) relations: Parent: class: Forum_Entry local: parent_entry_id foreign: id Thread: class: Forum_Thread local: thread_id foreign: id Forum_Thread: columns: board_id: integer(10) updated: integer(10) closed: integer(1) relations: Board: class: Forum_Board local: board_id foreign: id Entries: class: Forum_Entry local: id foreign: thread_id How to modify this schema, to use NestedSet (Tree structure of threads and entries)?

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  • Can't use where clause on correlated columns.

    - by Keyo
    I want to add a where clause to make sure video_count is greater than zero. Only categories which are referenced once or more in video_category.video_id should be returned. Because video_count is not a field in any table I cannot do this. Here is the query. SELECT category . * , ( SELECT COUNT( * ) FROM video_category WHERE video_category.category_id = category.category_id ) AS 'video_count' FROM category WHERE category.status = 1 AND video_count > '0' AND publish_date < NOW() ORDER BY updated DESC; Thanks for the help.

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  • Getting a ReturnValue from cmd.Parameters in c#?

    - by mark smith
    Hi, I have just finished converted a vb.net app to c# and one of the lines is to get @ReturnValue from the parameter. I ended up having to CAST a lot of things.. Is there not a easier way here is what i have int rc = ((System.Data.SqlTypes.SqlInt32)(((System.Data.SqlClient.SqlParameter)(cmd.Parameters["@ReturnValue"])).SqlValue)).Value; In vb.net it was as simple as doing this Dim rc As Integer = Convert.ToInt32(cmd.Parameters("@ReturnValue").Value) Alot easier :-) But the problem with C# is the property Value isn't available unless I Cast to SqlParameter and i also need to cast to Sqltypes.SqlInt32 - i can't just do a standard Convert.ToInt32

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  • Search a string to find which records in table are inside said string

    - by Improfane
    Hello, Say I have a string. Then I have a number of unique tokens or keywords, potentially a large number in a database. I want to search and find out which of these database strings are inside the string I provide (and get the IDs of them). Is there a way of using a query to search the provided string or must it be taken to application space? Am I right in thinking that this is not a 'full text search'? Would the best method be to insert it into the database to make it a full text search?

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  • How can I format Custom Data and display in autocomplete when source is an DB

    - by Andres Scarpone
    so I'm trying to get some info in the auto-complete widget like it's shown in the JQuery UI demo Demo, the only problem is they use a variable that they fill with the data they want to show, I instead want to access the data and the different description and stuff using a Data Base in MySQL, for this I have changed the source to use another php page that looks up the info. here is the code for the Auto-complete, I really don't understand the methods so I haven't changed it from the basic search. This is the JS: $(document).ready((function(){ $( "#completa" ).autocomplete({ source: "buscar.php", minLength: 1, focus: function (event, ui){ $("#completa").val(ui.item.val); return false; }; })); This is what I have in buscar.php: <?php $conec = mysql_connect(localhost, root, admin); if(!$conec) { die(mysql_error()); } else { $bd = mysql_select_db("ve_test",$conec ); if(!$bd) { die(mysql_error()); } } $termino = trim(strip_tags($_GET['term']));//Obtener el termino que envia el autocompletar $qstring = "SELECT name, descripcion FROM VE_table WHERE name LIKE '%".$termino."%'"; $result = mysql_query($qstring);//Solicitud a la Base de Datos while ($row = mysql_fetch_array($result,MYSQL_ASSOC))//Realizar un LOOP sobre los valores obtenidos { $row['value']=htmlentities(stripslashes($row['name'])); $row_set[] = $row;//build an array } echo json_encode($row_set);//Enviar los datos al autocompletar en codificacion JSON, Altamente Necesario. ?

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  • Converting MySQL Resultset from Rows to Columns

    - by gms8994
    I have output from a select like this: 04:47:37> select * from attributes left outer join trailer_attributes on attributes.id = trailer_attributes.attribute_id; +----+--------------+----------+-----------+------------+--------------+-----------------+ | id | name | datatype | list_page | trailer_id | attribute_id | attribute_value | +----+--------------+----------+-----------+------------+--------------+-----------------+ | 1 | Make | text | 1 | 1 | 1 | Apple | | 1 | Make | text | 1 | 2 | 1 | sdfg | | 2 | Year | number | 1 | 1 | 2 | 2009 | | 2 | Year | number | 1 | 2 | 2 | sdfg | | 3 | Type | text | 0 | 1 | 3 | iPhone | | 3 | Type | text | 0 | 2 | 3 | sdfg | | 4 | Axles | text | 0 | 1 | 4 | asdf | | 4 | Axles | text | 0 | 2 | 4 | sdfg | | 7 | Size | text | 0 | 1 | 7 | asd1 | | 7 | Size | text | 0 | 2 | 7 | sdfg | | 8 | Frame | text | 0 | 1 | 8 | | | 8 | Frame | text | 0 | 2 | 8 | sdfg | | 9 | Height | text | 0 | 1 | 9 | | | 9 | Height | text | 0 | 2 | 9 | sdfg | | 10 | Dollies | text | 0 | 1 | 10 | | | 10 | Dollies | text | 0 | 2 | 10 | sdfg | | 11 | Tires/Wheels | text | 0 | 1 | 11 | | | 11 | Tires/Wheels | text | 0 | 2 | 11 | sdfg | | 12 | Condition | text | 1 | 1 | 12 | New | | 12 | Condition | text | 1 | 2 | 12 | sdfg | | 13 | Title | text | 0 | 1 | 13 | | | 13 | Title | text | 0 | 2 | 13 | sdfg | +----+--------------+----------+-----------+------------+--------------+-----------------+ I want to convert it to something more along the lines of: id, Make, Year, Type, Axles, Size, Frame (etc) 1, Apple, 2009, iPhone, ..... 2, sdfg, sdfg, sdfg, ..... Any suggestions?

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  • Regarding some Update Stored procedure

    - by Serenity
    I have two Tables as follows:- Table1:- ------------------------------------- PageID|Content|TitleID(FK)|LanguageID ------------------------------------- 1 |abc |101 |1 2 |xyz |102 |1 -------------------------------------- Table2:- ------------------------- TitleID|Title |LanguageID ------------------------- 101 |Title1|1 102 |Title2|1 ------------------------ I don't want to add duplicates in my Table1(Content Table). Like..there can be no two Pages with the same Title. What check do I need to add in my Insert/Update Stored Procedure ? How do I make sure duplicates are never added. I have tried as follows:- CREATE PROC InsertUpdatePageContent ( @PageID int, @Content nvarchar(2000), @TitleID int ) AS BEGIN IF(@PageID=-1) BEGIN IF(NOT EXISTS(SELECT TitleID FROM Table1 WHERE LANGUAGEID=@LANGUAGEID)) BEGIN INSERT INTO Table1(Content,TitleID) VALUES(@Content,@TitleID) END END ELSE BEGIN IF(NOT EXISTS(SELECT TitleID FROM Table1 WHERE LANGUAGEID=@LANGUAGEID)) BEGIN UPDATE Table1 SET Content=@Content,TitleID=@TitleID WHERE PAGEID=@PAGEID END END END Now what is happening is that it is inserting new records alright and won't allow duplicates to be added but when I update its giving me problem. On my aspx Page I have a drop down list control that is bound to DataSource that returns Table 2(Title Table) and I have a text box in which user types Page's content to be stored. When I update, like lets say I have a row in my Table 1 as shown above with PageID=1. Now when I am updating this row, like I didn't change the Title from the drop down and only changed Content in the text box, its not updating the record ..and when Stored procedure's Update Query does not execute it displays a Label that says "Page with this title exists already." So whenever I am updating an existing record that label is displayed on screen.How do I change that IF condition in my Update Stored procedure?? EDIT:- @gbn :: Will that IF condition work in case of update? I mean lets say I am updating the Page with TitleID=1, I changed its content, then when I update, it's gonna execute that IF condition and it still won't update coz TitleID=1 already exits!It will only update if TitleID=1 is not there in Table1. Isn't it? Guess I am getting confused. Please answer.Thanks.

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  • Best way to get a reasonably random key for MYSQL records

    - by Steve N
    Hi there, I need to generate a reasonably random unique key for a table. It should be something like a GUID for MYSQL. I've tried UUID, but it looks like only the first few characters are actually random- the rest are the same every time I insert them. Essentially, it is desirable for this key field to be very difficult to guess, even if you already have one known value in the column. What is the best way to do this, and how should I set up the field data type to store the value efficiently? Thank you, Steve

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  • ASP.NET MVC 2 user input to SQL 2008 Database problems

    - by Rob
    After my publish in VS2010 the entire website loads and pulls data from the database perfectly. I can even create new users through the site with the correct key code, given out to who needs access. I have two connection strings in my web.config file The first: <add xdt:Transform="SetAttributes" xdt:Locator="Match(name)" name="EveModelContainer" connectionString="metadata=res://*/Models.EdmModel.EveModel.csdl|res://*/Models.EdmModel.EveModel.ssdl|res://*/Models.EdmModel.EveModel.msl;provider=System.Data.SqlClient;provider connection string=&quot;Data Source=localhost;Initial Catalog=fleet;Persist Security Info=True;User ID=fleet;Password=****&quot;" providerName="System.Data.EntityClient" /> The second: <add xdt:Transform="SetAttributes" xdt:Locator="Match(name)" name="ApplicationServices" connectionString="Data Source=localhost;Initial Catalog=fleet;Persist Security Info=True;User ID=fleet;Password=****;MultipleActiveResultSets=True" /> The first one is the one that is needed to post data with the main application, EveModelContainer. Everything else is pulled using the standard ApplicationServices connection. Do you see anything wrong with my connectionstring? I'm at a complete loss here. The site works perfectly on my friends server and not on mine... Could it be a provider issue? And if I go to iis 7's manager console, and click .net users I get a pop up message saying the custom provider isn't a trusted provider do I want to allow it to run at a higher trust level. I'm at the point where I think its either my string or this trusted provider error... but I have no clue how to add to the trusted provider list... Thank you in advance!!!

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  • What is the corrrect way to increment a field making up part of a composit key

    - by Tr1stan
    I have a bunch of tables whose primary key is made up of the foreign keys of other tables (Composite key). Therefore for example the attributes (as a very cut down version) might look like this: A[aPK, SomeFields] 1:M B[bPK, aFK, SomeFields] 1:M C[cPK, bFK, aFK, SomeFields] as data this could look like: A[aPK, SomeFields]: 1, Foo 2, Bar B[bPK, aFK, SomeFields]: 1, 1, FooData1 2, 1, FooData2 1, 2, BarData1 2, 2, BarData2 C[cPK, bFK, aFK, SomeFields]: 1, 1, 1, FooData1More 2, 1, 1, FooData1More 1, 2, 1, FooData2More 2, 2, 1, FooData2More 1, 1, 2, BarData1More 2, 1, 2, BarData1More 1, 2, 2, BarData2More 2, 2, 2, BarData2More I've got this running in a MSSQL DBMS and I'm looking for the best way to increment the left most column, in each table when a new tuple is added to it. I can't use the Auto Increment Identity Specification option as that has no idea that it is part of a composite key. I also don't want to use any aggregate function such as: MAX(field)+1 as this will have adverse affects with multiple users inputting data, rolling back etc. There might however be a nice trigger based option here, but I'm not sure. This must be a common issue so I'm hoping that someone has a lovely solution. As a side which may or may not affect the answer, I'm using Entity Framework 1.0 as my ORM, within a c# MVC application.

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  • Merge computed data from two tables back into one of them

    - by Tyler McHenry
    I have the following situation (as a reduced example). Two tables, Measures1 and Measures2, each of which store an ID, a Weight in grams, and optionally a Volume in fluid onces. (In reality, Measures1 has a good deal of other data that is irrelevant here) Contents of Measures1: +----+----------+--------+ | ID | Weight | Volume | +----+----------+--------+ | 1 | 100.0000 | NULL | | 2 | 200.0000 | NULL | | 3 | 150.0000 | NULL | | 4 | 325.0000 | NULL | +----+----------+--------+ Contents of Measures2: +----+----------+----------+ | ID | Weight | Volume | +----+----------+----------+ | 1 | 75.0000 | 10.0000 | | 2 | 400.0000 | 64.0000 | | 3 | 100.0000 | 22.0000 | | 4 | 500.0000 | 100.0000 | +----+----------+----------+ These tables describe equivalent weights and volumes of a substance. E.g. 10 fluid ounces of substance 1 weighs 75 grams. The IDs are related: ID 1 in Measures1 is the same substance as ID 1 in Measures2. What I want to do is fill in the NULL volumes in Measures1 using the information in Measures2, but keeping the weights from Measures1 (then, ultimately, I can drop the Measures2 table, as it will be redundant). For the sake of simplicity, assume that all volumes in Measures1 are NULL and all volumes in Measures2 are not. I can compute the volumes I want to fill in with the following query: SELECT Measures1.ID, Measures1.Weight, (Measures2.Volume * (Measures1.Weight / Measures2.Weight)) AS DesiredVolume FROM Measures1 JOIN Measures2 ON Measures1.ID = Measures2.ID; Producing: +----+----------+-----------------+ | ID | Weight | DesiredVolume | +----+----------+-----------------+ | 4 | 325.0000 | 65.000000000000 | | 3 | 150.0000 | 33.000000000000 | | 2 | 200.0000 | 32.000000000000 | | 1 | 100.0000 | 13.333333333333 | +----+----------+-----------------+ But I am at a loss for how to actually insert these computed values into the Measures1 table. Preferably, I would like to be able to do it with a single query, rather than writing a script or stored procedure that iterates through every ID in Measures1. But even then I am worried that this might not be possible because the MySQL documentation says that you can't use a table in an UPDATE query and a SELECT subquery at the same time, and I think any solution would need to do that. I know that one workaround might be to create a new table with the results of the above query (also selecting all of the other non-Volume fields in Measures1) and then drop both tables and replace Measures1 with the newly-created table, but I was wondering if there was any better way to do it that I am missing.

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  • what type of errors can we handle using system define unnamed exception in sqlplus?

    - by Aspirant
    I have been trying to access the below code DECLARE N_DEPTNO DEPT.DEPTNO %TYPE :=&DEPT_NUM; V_DNAME DEPT.DNAME %TYPE; NOT_ENOUGH_VALUES EXCEPTION; PRAGMA EXCEPTION_INIT(NOT_ENOUGH_VALUES,-06502); BEGIN SELECT DNAME,LOC INTO DNAME FROM DEPT WHERE DEPTNO = N_DEPTNO; DBMS_OUTPUT.PUT_LINE('Successfully Fetched !!'); EXCEPTION WHEN NOT_ENOUGH_VALUES THEN DBMS_OUTPUT.PUT_LINE('No Enough Values ... '); END; It is still showing error message after specified it in EXCEPTION block. Can i handle these type of errors using PRAGMA EXCEPTION_INIT i.e not providing enough values in the select statement... If not what type of errors can be handled in System Defined Unnamed Exception using PRAGMA EXCEPTION_INIT.

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