Search Results

Search found 26115 results on 1045 pages for 'table alias'.

Page 433/1045 | < Previous Page | 429 430 431 432 433 434 435 436 437 438 439 440  | Next Page >

  • What are the best practices for storing PHP session data in a database?

    - by undefined
    I have developed a web application that uses a web server and database hosted by a web host (on the ground) and a server running on Amazon Web Services EC2. Both servers may be used by a user during a session and both will need to know some session information about a user. I don't want to POST the information that is needed by both servers because I dont want it to be visible to browsers / Firebug etc. So I need my session data to persist across servers. And I think that this means that the best option is to store all / some of the data that I need in the database rather than in a session. The easiest thing to do seems to be to keep the sessions but to POST the session_id between servers and use this as the key to lookup the data I need from a 'user_session_data' table in the database. I have looked at Tony Marston's article "Saving PHP Session Data to a database" - should I use this or will a table with the session data that I need and session_id as key suffice? What would be the downside of creating my own table and set of methods for storing the data I need in the database?

    Read the article

  • Hibernate mapping Problem

    - by Geln Yang
    Hi, There is a table Item like, code,name 01,parent1 02,parent2 0101,child11 0102,child12 0201,child21 0202,child22 Create a java object and hbm xml to map the table.The Item.parent is a Item whose code is equal to the first two characters of its code : class Item{ String code; String name; Item parent; List<Item> children; .... setter/getter.... } <hibernate-mapping> <class name="Item" table="Item"> <id name="code" length="4" type="string"> <generator class="assigned" /> </id> <property name="name" column="name" length="50" not-null="true" /> <many-to-one name="parent" class="Item" not-found="ignore"> <formula> <![CDATA[ (select i.code,r.name from Item i where (case length(code) when 4 then i.code=SUBSTRING(code,1,2) else false end)) ]]> </formula> </many-to-one> <bag name="children"></bag> </class> </hibernate-mapping> I try to use formula to define the many-to-one relationship,but it doesn't work!Is there something wrong?Or is there other method? Thanks! ps,I use mysql database.

    Read the article

  • query structure - ignoring entries for the same event from multiple users?

    - by Andrew Heath
    One table in my MySQL database tracks game plays. It has the following structure: SCENARIO_VICTORIES [ID] [scenario_id] [game] [timestamp] [user_id] [winning_side] [play_date] ID is the autoincremented primary key. timestamp records the moment of submission for the record. winning_side has one of three possible values: 1, 2, or 0 (meaning a draw) One of the queries done on this table calculates the victory percentage for each scenario, when that scenario's page is viewed. The output is expressed as: Side 1 win % Side 2 win % Draw % and queried with: SELECT winning_side, COUNT(scenario_id) FROM scenario_victories WHERE scenario_id='$scenID' GROUP BY winning_side ORDER BY winning_side ASC and then processed into the percentages and such. Sorry for the long setup. My problem is this: several of my users play each other, and record their mutual results. So these battles are being doubly represented in the victory percentages and result counts. Though this happens infrequently, the userbase isn't large and the double entries do have a noticeable effect on the data. Given the table and query above - does anyone have any suggestions for how I can "collapse" records that have the same play_date & game & scenario_id & winning_side so that they're only counted once?

    Read the article

  • Align div inline

    - by Rajeev
    How to make the second div inline to the first div.I need the flash swf to appear next to the tds <html> <div style="display: inline"> <table style="table-layout:fixed;width:100%;"> <tr> <td width ="20%"> </td> </tr> <tr> <td width="20%"> 1.Can you view the image? </td> <td width="20%"> 1.Can you upload the image? </td> </tr> </table> </div> <div style="display: inline;"> <object width="100" height="100"> <embed src="image_tr.swf" width="250" height="250"> </embed> </object> </div>

    Read the article

  • What noncluster index would be better to create on SQL Server?

    - by Junior Mayhé
    Here I am studying nonclustered indexes on SQL Server Management Studio. I've created a table with more than 1 million records. This table has a primary key. SELECT CustomerName FROM Customers Which leads the execution plan to show me: I/O cost = 3.45646 Operator cost = 4.57715 For the first attempt to improve performance, I've created a nonclustered index for this table: CREATE NONCLUSTERED INDEX [IX_CustomerID_CustomerName] ON [dbo].[Customers] ( [CustomerId] ASC, [CustomerName] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] GO With this first try, I've executed the select statement and the execution plan shows me: I/O cost = 2.79942 Operator cost = 3.92001 Now the second try, I've deleted this nonclustered index in order to create a new one. CREATE NONCLUSTERED INDEX [IX_CategoryName] ON [dbo].[Categories] ( [CategoryId] ASC ) INCLUDE ( [CategoryName]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] GO With this second try, I've executed the select statement and the execution plan shows me the same result: I/O cost = 2.79942 Operator cost = 3.92001 Am I doing something wrong or this is expected? Shall I use the first nonclustered index with two fields, or the second nonclustered with one field (CategoryID) including the second field (CategoryName)?

    Read the article

  • Mysql many to many problem (leaderborad/scoreboard)

    - by zoko2902
    Hi all! I'm working on a small project in regards of the upcoming World Cup. I'm building a roster/leaderboard/scoredboard based on groups with national teams. The idea is to have information on all upcoming matches within the group or in the knockout phase (scores, time of the match, match stats etc.). Currently I'm stuck with the DB in that I can't come up with a query that would return paired teams in a row. I have these 3 tables: CREATE TABLE IF NOT EXISTS `wc_team` ( `id` INT NOT NULL AUTO_INCREMENT , `name` VARCHAR(45) NULL , `description` VARCHAR(250) NULL , `flag` VARCHAR(45) NULL , `image` VARCHAR(45) NULL , `added` TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP , PRIMARY KEY (`id`) , CREATE TABLE IF NOT EXISTS `wc_match` ( `id` INT NOT NULL AUTO_INCREMENT , `score` VARCHAR(6) NULL , `date` DATE NULL , `time` VARCHAR(45) NULL , `added` TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP , PRIMARY KEY (`id`) , CREATE TABLE IF NOT EXISTS `wc_team_has_match` ( `wc_team_id` INT NOT NULL , `wc_match_id` INT NOT NULL , PRIMARY KEY (`wc_team_id`, `wc_match_id`) , I've simplified the tables so we don't go in the wrong direction. Now I've tried al kinds of joins and groupings I could think of, but I never seem to get. Example guery: SELECT t.wc_team_id,t.wc_match_id,c.id.c.name,d.id,d.name FROM wc_team_has_match AS t LEFT JOIN wc_match AS s ON t.wc_match_id = s.id LEFT JOIN wc_team AS c ON t.wc_team_id = c.id LEFT JOIN wc_team AS d ON t.wc_team_id = d.id Which returns: wc_team_id wc_match_id id name id name 16 5 16 Brazil 16 Brazil 18 5 18 Argentina 18 Argentina But what I really want is: wc_team_id wc_match_id id name id name 16 5 16 Brazil 18 Argentina Keep in mind that a group has more matches I want to see all those matches not only one. Any pointer or suggestion would be extremly appreciated since I'm stuck like a duck on this one :).

    Read the article

  • Does a Postgresql dump create sequences that start with - or after - the last key?

    - by bennylope
    I recently created a SQL dump of a database behind a Django project, and after cleaning the SQL up a little bit was able to restore the DB and all of the data. The problem was the sequences were all mucked up. I tried adding a new user and generated the Python error IntegrityError: duplicate key violates unique constraint. Naturally I figured my SQL dump didn't restart the sequence. But it did: DROP SEQUENCE "auth_user_id_seq" CASCADE; CREATE SEQUENCE "auth_user_id_seq" INCREMENT 1 START 446 MAXVALUE 9223372036854775807 MINVALUE 1 CACHE 1; ALTER TABLE "auth_user_id_seq" OWNER TO "db_user"; I figured out that a repeated attempt at creating a user (or any new row in any table with existing data and such a sequence) allowed for successful object/row creation. That solved the pressing problem. But given that the last user ID in that table was 446 - the same start value in the sequence creation above - it looks like Postgresql was simply trying to start creating rows with that key. Does the SQL dump provide the wrong start key by 1? Or should I invoke some other command to start sequences after the given start ID? Keenly curious.

    Read the article

  • jQuery re-checking check boxes

    - by Jacob
    Hi, I having problems with re-checking some checkboxes after and ajax call updates a table. I have a table of what the project calls 'shares'. I want to: 1) check for and save any checked shares to an array 2) Do my ajax call to update the table of shares 3) Re-check any there we checked before the ajax update. My code is not working and I can't see why? Any tips, help or advise much appreciated. // Array to hold our checked share ids var savedShareIDs = new Array(); // Add checked share ids into array $("input:checkbox[name=share_ids]:checked").each(function() { savedShareIDs.push($(this).val()); }); // Do ajax update Dajaxice.pagination_shares('Dajax.process',{'id':1, 'page':1}) // Re-check any that were checked before ajax update $("input:checkbox[name=share_ids]").each(function() { if ( $.inArray( $(this).val(), savedShareIDs) > -1 ) { $(this).attr('checked',true) } }); The problem is the checkboxes are not checking. I'm pretty sure the loop is working and the inArray check works. Just not checking the checkboxes. Can anyone see where I'm going wrong? Thanks.

    Read the article

  • select from multiple tables but ordering by a datetime field

    - by Chris Mccabe
    I have 3 tables that are unrelated (related that each contains data for a different social network). Each has a datetime field dated- I'm already grouping by hour as you can see below (this one below for linked_in) SELECT count(*), date_format(dated, '%Y:%m:%d %H') as hour FROM upd8r_linked_in_accts WHERE CAST(dated AS DATE) = '".$start_date."' GROUP BY hour I would like to know how to do a total across all 3 networks- the tables for the three are CREATE TABLE IF NOT EXISTS `upd8r_facebook_accts` ( `id` int(11) NOT NULL AUTO_INCREMENT, `owner_id` varchar(50) NOT NULL, `user_id` int(11) NOT NULL, `fb_id` bigint(30) NOT NULL, `dated` datetime NOT NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=80 ; CREATE TABLE IF NOT EXISTS `upd8r_linked_in_accts` ( `id` int(11) NOT NULL AUTO_INCREMENT, `owner_id` varchar(50) NOT NULL, `user_id` int(11) NOT NULL, `linked_in` varchar(200) NOT NULL, `oauth_secret` varchar(100) NOT NULL, `first_count` int(11) NOT NULL, `second_count` int(11) NOT NULL, `dated` datetime NOT NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=200 ; CREATE TABLE IF NOT EXISTS `upd8r_twitter_accts` ( `id` int(11) NOT NULL AUTO_INCREMENT, `owner_id` varchar(50) NOT NULL, `user_id` int(11) NOT NULL, `twitter` varchar(200) NOT NULL, `twitter_secret` varchar(100) NOT NULL, `dated` datetime NOT NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=9 ; something like this ? (SELECT count(*), date_format(dated, '%Y:%m:%d %H') as hour FROM upd8r_linked_in_accts WHERE CAST(dated AS DATE) = '".$start_date."') UNION ALL (SELECT count(*), date_format(dated, '%Y:%m:%d %H') as hour FROM upd8r_facebook_accts WHERE CAST(dated AS DATE) = '".$start_date."') UNION ALL (SELECT count(*), date_format(dated, '%Y:%m:%d %H') as hour FROM upd8r_twitter_accts WHERE CAST(dated AS DATE) = '".$start_date."') UNION ALL GROUP BY hour

    Read the article

  • [C#] Linq doesn't insert associated entity on insert.

    - by Tomek
    Hello! I have simple mapping: [Table(Name="Person")] public class Person { private int id; private int state_id; private EntityRef<PersonState> state = new EntityRef<PersonState>(); [Column(IsPrimaryKey = true, Storage = "id", Name="id", IsDbGenerated = true, CanBeNull = false)] public int ID { get { return id; } set { id = value; } } [Column(Storage="state_id", Name="state_id")] public int StateID { get{ return state_id;} set{ state_id = value;} } [Association( Storage = "state", ThisKey = "StateID", IsForeignKey=true)] public PersonState State { get { return state.Entity; } set { state.Entity = value; } } } [Table(Name = "PersonState")] public class PersonState { private int id; private State state; [Column(Name="id", Storage="id", IsDbGenerated=true, IsPrimaryKey=true)] public int ID { get { return id; } set { id = value; } } [Column(Name = "date", Storage = "date")] public DateTime Date { get { return date; } set { date = value; } } [Column(Name = "type", Storage = "state")] public State State { get { return state; } set { state = value; } } } I use this code to insert new person with default state: private static Person NewPerson() { Person p = new Person(); p.State = DefaultState(p); return p; } private static PersonState DefaultState() { PersonState state = new PersonState(); state.Date = DateTime.Now; state.State = State.NotNotified; state.Comment = "Default State!"; return state; } Leater in code: db.Persons.InsertOnSubmit(NewPerson()); db.SubmitChanges(); In database(sqlite) I have all new persons, but state_id of all persons is set to 0, and PersonState table is empty. Why Linq did not insert any State object to database?

    Read the article

  • Database schema for Product Properties

    - by Chemosh
    As so many people I'm looking for a Products /Product Properties database schema. I'm using Ruby on Rails and (Thinking) Sphinx for faceted searches. Requirements: Adding new product types and their options should not require a change to the database schema Support faceted searches using Sphinx. Solutions I've come across: (See Bill Karwin's answer) Option 1: Single Table Inheritance Not an option really. The table would contain way to many columns. Option 2: Class Table Inheritance Ruby on Rails caches the database schema on start-up which means a restart whenever a new type of product is introduced. If you have a size able product catalog this could mean hundreds of tables. Option 3: Serialized LOB Kills being able to do faceted searches without heavy application logic. Option 4: Entity-Attribute-Value For testing purposes, EAV worked fine. However it could quickly become a mess and a maintenance hell as you add more and more options (e.g. when an option increase the prices or delivery time). What option should I go with? What other solutions are out there? Is there a silver bullet (ha) I overlooked?

    Read the article

  • WCF data services (OData), query with inheritance limitation?

    - by Mathieu Hétu
    Project: WCF Data service using internally EF4 CTP5 Code-First approach. I configured entities with inheritance (TPH). See previous question on this topic: Previous question about multiple entities- same table The mapping works well, and unit test over EF4 confirms that queries runs smoothly. My entities looks like this: ContactBase (abstract) Customer (inherits from ContactBase), this entity has also several Navigation properties toward other entities Resource (inherits from ContactBase) I have configured a discriminator, so both Customer and Resource map to the same table. Again, everythings works fine on the Ef4 point of view (unit tests all greens!) However, when exposing this DBContext over WCF Data services, I get: - CustomerBases sets exposed (Customers and Resources sets seems hidden, is it by design?) - When I query over Odata on Customers, I get this error: Navigation Properties are not supported on derived entity types. Entity Set 'ContactBases' has a instance of type 'CodeFirstNamespace.Customer', which is an derived entity type and has navigation properties. Please remove all the navigation properties from type 'CodeFirstNamespace.Customer'. Stacktrace: at System.Data.Services.Serializers.SyndicationSerializer.WriteObjectProperties(IExpandedResult expanded, Object customObject, ResourceType resourceType, Uri absoluteUri, String relativeUri, SyndicationItem item, DictionaryContent content, EpmSourcePathSegment currentSourceRoot) at System.Data.Services.Serializers.SyndicationSerializer.WriteEntryElement(IExpandedResult expanded, Object element, ResourceType expectedType, Uri absoluteUri, String relativeUri, SyndicationItem target) at System.Data.Services.Serializers.SyndicationSerializer.<DeferredFeedItems>d__b.MoveNext() at System.ServiceModel.Syndication.Atom10FeedFormatter.WriteItems(XmlWriter writer, IEnumerable`1 items, Uri feedBaseUri) at System.ServiceModel.Syndication.Atom10FeedFormatter.WriteFeedTo(XmlWriter writer, SyndicationFeed feed, Boolean isSourceFeed) at System.ServiceModel.Syndication.Atom10FeedFormatter.WriteFeed(XmlWriter writer) at System.ServiceModel.Syndication.Atom10FeedFormatter.WriteTo(XmlWriter writer) at System.Data.Services.Serializers.SyndicationSerializer.WriteTopLevelElements(IExpandedResult expanded, IEnumerator elements, Boolean hasMoved) at System.Data.Services.Serializers.Serializer.WriteRequest(IEnumerator queryResults, Boolean hasMoved) at System.Data.Services.ResponseBodyWriter.Write(Stream stream) Seems like a limitation of WCF Data services... is it? Not much documentation can be found on the web about WCF Data services (OData) and inheritance specifications. How can I overpass this exception? I need these navigation properties on derived entities, and inheritance seems the only way to provide mapping of 2 entites on the same table with Ef4 CTP5... Any thoughts?

    Read the article

  • How to Map Two Tables To One Class in Fluent NHibernate

    - by Richard Nagle
    I am having a problem with fluent nhiberbate mapping two tables to one class. I have the following database schema: TABLE dbo.LocationName ( LocationId INT PRIMARY KEY, LanguageId INT PRIMARY KEY, Name VARCHAR(200) ) TABLE dbo.Language ( LanguageId INT PRIMARY KEY, Locale CHAR(5) ) And want to build the following class definition: public class LocationName { public virtual int LocationId { get; private set; } public virtual int LanguageId { get; private set; } public virtual string Name { get; set; } public virtual string Locale { get; set; } } Here is my mapping class: public LocalisedNameMap() { WithTable("LocationName"); UseCompositeId() .WithKeyProperty(x => x.LanguageId) .WithKeyProperty(x => x.LocationId); Map(x => x.Name); WithTable("Language", lang => { lang.WithKeyColumn("LanguageId"); lang.Map(x => x.Locale); }); } The problem is with the mapping of the Locale field being from another table, and in particular that the keys between those tables don't match. Whenever I run the application with this mapping I get the following error on startup: Foreign key (FK7FC009CCEEA10EEE:Language [LanguageId])) must have same number of columns as the referenced primary key (LocationName [LanguageId, LocationId]) How do I tell nHibernate to map from LocationName to Language using only the LanguageId field?

    Read the article

  • Can CSS change the apparent sequence of elements, e.g. using float or position?

    - by ChrisW
    Edit: answer to this question is easy, a simple example of float left and float right. I'd like to float some annotations to the left of a topic using HTML and CSS, for example the 'status' and 'author' annotations shown in the following mockup/image: For semantic reasons, perhaps: I prefer to use CSS instead of a table-based layout In the HTML, the status should appear after the corresponding heading For example: <h1>This is a section title</h1> <div class="status">approved</div> <div class="author">chris</div> <p>This is some text. Lorem ipsum.</p> <p>Lorem ipsum.</p> <h1>Different section title</h1> <div class="status">rejected</div> <p>Lorem ipsum.</p> I'd like the annotations to be after the heading in the HTML, because everything associated with (i.e. the contents of) a topic is usually whatever is after the topic's heading. However I'd like the annotations to be displayed before (to the left of) the heading, as illustrated above. Is this possible? What is the most semantic HTML, and corresponding CSS, that will render as shown above? Would you recommend a table-based layout instead? Even if that means putting the headings in a table cell? It may not be possible; this answer suggests it isn't possible ... but I don't know CSS well enough to say that for sure.

    Read the article

  • CodeIgnither OAuth 2.0 database setup for users and access_tokens

    - by xref
    Per this question I am using CodeIgniter and OAuth 2 in an attempt to provide SSO for internal users of my webapp, ideally verifying them against their Google Apps account. No registrations or anything, just existing users. Using the CI oauth2 spark I'm getting back from Google an OAuth token similar to below: OAuth2_Token_Access Object ( [access_token:protected] => dp83.AHSDj899sDHHD908DHFBDjidkd8989dDHhjjd [expires:protected] => 1349816820 [refresh_token:protected] => [uid:protected] => ) And using that token I can retrieve some user info from Google: [uid] => 3849450385394595 [nickname] => this_guy [name] => This Guy [first_name] => This [last_name] => Guy [email] => [email protected] [location] => [image] => [description] => [urls] => Array ( ) Now to allow the 15 people or so who will be using the webapp currently to log in, do I need to create a users table in the mysql database with their email address as a key? Then compare the email which just came back from the Google OAuth request and see if it exists in my users table? What about the Google access_token, do I store that now along with the email which already existed in the users table? Related: How would I go about verifying the user automatically in the future against that access_token so they don't have to go through the whole OAuth approval process with Google again?

    Read the article

  • Crosstab with multiple items

    - by Michael Wexler
    In SPSS, it is (relatively) easy to create a cross tab with multiple variables using the factors as the table heading. So, something like the following (made up data, etc.). Q1, Q2, and Q3 each have either a 1, a 2, or a 3 for each person. 1 (very Often) 2 (Rarely) 3 (Never) Q1. Likes it 12 15 13 Q2. Recommends it 22 11 10 Q3. Used it 22 12 9 In SPSS, one can even request row, column, or total percentages. I've tried table(), ftable(), xtab(), CrossTable() from gmodels, and CrossTable() from descr, and none of these can handle (afaik) multiple variables; they mostly seem to handle 1 variable crossed with another variable, and the 3rd creates layers. Is there a package with some good cross tabbing/table examples that I could use to figure this out? I'm sure I'm missing something simple, so I appreciate you pointing out what I missed. Perhaps I have to generate each row as a separate list and then make a dataframe and print the dataframe?

    Read the article

  • Mysql partitioning: Partitions outside of date range is included

    - by Sturlum
    Hi, I have just tried to configure partitions based on date, but it seems that mysql still includes a partition with no relevant data. It will use the relevant partition but also include the oldest for some reason. Am I doing it wrong? The version is 5.1.44 (MyISAM) I first added a few partitions based on "day", which is of type "date" ALTER TABLE ptest PARTITION BY RANGE(TO_DAYS(day)) ( PARTITION p1 VALUES LESS THAN (TO_DAYS('2009-08-01')), PARTITION p2 VALUES LESS THAN (TO_DAYS('2009-11-01')), PARTITION p3 VALUES LESS THAN (TO_DAYS('2010-02-01')), PARTITION p4 VALUES LESS THAN (TO_DAYS('2010-05-01')) ); After a query, I find that it uses the "old" partition, that should not contain any relevant data. mysql> explain partitions select * from ptest where day between '2010-03-11' and '2010-03-12'; +----+-------------+------------+------------+-------+---------------+------+---------+------+------+-------------+ | id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+------------+------------+-------+---------------+------+---------+------+------+-------------+ | 1 | SIMPLE | ptest | p1,p4 | range | day | day | 3 | NULL | 79 | Using where | +----+-------------+------------+------------+-------+---------------+------+---------+------+------+-------------+ When I select a single day, it works: mysql> explain partitions select * from ptest where day = '2010-03-11'; +----+-------------+------------+------------+------+---------------+------+---------+-------+------+-------+ | id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+------------+------------+------+---------------+------+---------+-------+------+-------+ | 1 | SIMPLE | ptest | p4 | ref | day | day | 3 | const | 39 | | +----+-------------+------------+------------+------+---------------+------+---------+-------+------+-------+

    Read the article

  • jcarousel not working in IE

    - by pradeep
    i have used jcarousel for my slideshow. it does not work in IE http://ratingscorner.com/product_rating.php?alias=Rashtreeya-Vidyalaya-College-of-Engineering-Mysore-Road-Bangalore&product=colleges any help on it.?

    Read the article

  • LINQ Joins - Performance

    - by Meiscooldude
    I am curious on how exactly LINQ (not LINQ to SQL) is performing is joins behind the scenes in relation to how Sql Server performs joins. Sql Server before executing a query, generates an Execution Plan. The Execution Plan is basically an Expression Tree on what it believes is the best way to execute the query. Each node provides information on whether to do a Sort, Scan, Select, Join, ect. On a 'Join' node in our execution plan, we can see three possible algorithms; Hash Join, Merge Join, and Nested Loops Join. Sql Server will choose which algorithm to for each Join operation based on expected number of rows in Inner and Outer tables, what type of join we are doing (some algorithms don't support all types of joins), whether we need data ordered, and probably many other factors. Join Algorithms: Nested Loop Join: Best for small inputs, can be optimized with ordered inner table. Merge Join: Best for medium to large inputs sorted inputs, or an output that needs to be ordered. Hash Join: Best for medium to large inputs, can be parallelized to scale linearly. LINQ Query: DataTable firstTable, secondTable; ... var rows = from firstRow in firstTable.AsEnumerable () join secondRow in secondTable.AsEnumerable () on firstRow.Field<object> (randomObject.Property) equals secondRow.Field<object> (randomObject.Property) select new {firstRow, secondRow}; SQL Query: SELECT * FROM firstTable fT INNER JOIN secondTable sT ON fT.Property = sT.Property Sql Server might use a Nested Loop Join if it knows there are a small number of rows from each table, a merge join if it knows one of the tables has an index, and Hash join if it knows there are a lot of rows on either table and neither has an index. Does Linq choose its algorithm for joins? or does it always use one?

    Read the article

  • Embed flash ActiveX in vb6 dynamically?

    - by Alex
    im trying to embed flash in my program by placing flash.ocx in my app's folder without having to register it. i found DirectCom.dll and with this code i can show the right version of flash. but how do i show it on the form and load the movie? Private Declare Function GetInstanceOld Lib "DirectCom" Alias "GETINSTANCE" (FName As String, ClassName As String) As Object Dim ShockwaveFlash1 As Object Set ShockwaveFlash1 = GetInstanceEx(StrPtr(App.Path & "\" & "flash.ocx"), StrPtr("ShockwaveFlash"), True) MsgBox ShockwaveFlash1.FlashVersion

    Read the article

  • customer.name joining transactions.name vs. customer.id [serial] joining transactions.id [integer]

    - by Frank Computer
    INFORMIX-SQL 7.32 Pawnshop Application: one-to-many relationship where each customer (master) can have many transactions (detail). customer( id serial, pk_name char(30), {PATERNAL-NAME MATERNAL-NAME, FIRST-NAME MIDDLE-NAME} [...] ); unique index on id; unique cluster index on name; transaction( fk_name char(30), ticket_number serial, [...] ); dups cluster index on fk_name; unique index on ticket_number; Several people have told me this is not the correct way to join master to detail. They said I should always join customer.id[serial] to transactions.id[integer]. When a customer pawns merchandise, clerk queries the master using wildcards on name. The query usually returns several customers, clerk scrolls until locating the right name, enters a 'D' to change to detail transactions table, all transactions are automatically queried, then clerk enters an 'A' to add a new transaction. The problem with using customer.id joining transaction.id is that although the customer table is maintained in sorted name order, clustering the transaction table by fk_id groups the transactions by fk_id, but they are not in the same order as the customer name, so when clerk is scrolling through customer names in the master, the system has to jump allover the place to locate the clustered transactions belonging to each customer. As each new customer is added, the next id is assigned to that customer, but new customers dont show up in alphabetical order. I experimented using id joins and confirmed the decrease in performance. How can I use id joins instead of name joins and still preserve the clustered transaction order by name if transactions has no name column?

    Read the article

  • php - create columns from mysql list

    - by user271619
    I have a long list generated from a simple mysql select query. Currently (shown in the code below) I am simply creating list of table rows with each record. So, nothing complicated. However, I want to divide it into more than one column, depending on the number of returned results. I've been wrapping my brain around how to count this in the php, and I'm not getting the results I need. <table> <? $query = mysql_query("SELECT * FROM `sometable`"); while($rows = mysql_fetch_array($query)){ ?> <tr> <td><?php echo $rows['someRecord']; ?></td> </tr> <? } ?> </table> Obviously there's one column generated. So if the records returned reach 10, then I want to create a new column. In other words, if the returned results are 12, I have 2 columns. If I have 22 results, I'll have 3 columns, and so on.

    Read the article

  • nHibernate storage of an object with self referencing many children and many parents

    - by AdamC
    I have an object called MyItem that references children in the same item. How do I set up an nhibernate mapping file to store this item. public class MyItem { public virtual string Id {get;set;} public virtual string Name {get;set;} public virtual string Version {get;set;} public virtual IList<MyItem> Children {get;set;} } So roughly the hbm.xml would be: <class name="MyItem" table="tb_myitem"> <id name="Id" column="id" type="String" length="32"> <generator class="uuid.hex" /> </id> <property name="Name" column="name" /> <property name="Version" column="version" /> <bag name="Children" cascade="all-delete-orphan" lazy="false"> <key column="children_id" /> <one-to-many class="MyItem" not-found="ignore"/> </bag> </class> This wouldn't work I don't think. Perhaps I need to create another class, say MyItemChildren and use that as the Children member and then do the mapping in that class? This would mean having two tables. One table holds the MyItem and the other table holds references from my item. NOTE: A child item could have many parents.

    Read the article

< Previous Page | 429 430 431 432 433 434 435 436 437 438 439 440  | Next Page >