Search Results

Search found 4815 results on 193 pages for 'parameterized queries'.

Page 69/193 | < Previous Page | 65 66 67 68 69 70 71 72 73 74 75 76  | Next Page >

• SQL Server 2008 spatial index and CPU utilization with MapGuide Open Source 2.1

  - by Antonio de la Peña

  I have a SQL Server table with hundreds of thousands of geometry type parcels. I have made indexes on them trying different combinations of density and objects per cell settings. So far I'm settiling for LOW, LOW, MEDIUM, MEDIUM and 16 objects per cell and I made a SP that sets the bounding box according to the extents of the entities in the table. There is an incredible performance boost from queries taking almost minutes without index to less than seconds, it gets faster when the zoom is closer thus less objects are displayed. Yet the CPU utilization gets to 100% when querying for features, even when the queries themselves are fast. I'm worrying this will not fly in a production environment. I am using MapGuide Open Source 2.1 for this project, but I am positive the CPU load is caused by SQL Server. I wonder if my indexes are set properly. I haven't found any clear documentation on how to properly set them up. Every article I've read basically says "it depends..." but nothing specific. Do you have any recommendations for me, including books, articles? Thank you.

  Read the article

• Webmethod on my C# (server side) doesn't return data to client side (javascript)

  - by Philo

  I am using a c# Webmethod to return results to my client side written in Javascript. [WebMethod] public static string MyMethod(string Id) { SQL QUERIES and then .... // adding data to member class. Member member = new Member(Name, DOB, Sex, Member_Identification, Dates_of_services); return JsonConvert.SerializeObject(member); <-- member is a class of List strings } And on the client side you could invoke this method using the jQuery.ajax() function like this: $.ajax({ url: 'default.aspx/MyMethod', type: 'POST', contentType: 'application/json; charset=utf-8', data: JSON.stringify({ ID : ID }), success: on success { } }); function onSuccess(data) { // parses json returned data var jsondata = $.parseJSON(data.d); ..... } Now the data returned to the client side are Lists of Strings. This method works for me most times. However for one or two queries, the method runs forever without returning to the client side. On the server side however, I can use breakpoints and see that all the Lists of strings have been formed correctly. But I cannot seem to find out why they are never returned to the client side. My code reaches till the return statement on the server side and then the program just runs forever. It never reaches the function 'onsuccess' Can anyone tell me why this can happen? Anomalies in data maybe?

  Read the article

• Bulletin board - Database optimisation

  - by andrew

  This question is a follow on from this Question The project and problem The project I am currently working on is a bulletin board for a large non-profit organisation. The bulletin board will be used to allow inter-office communication within the organisation. I am building the application and have been having trouble extracting the results that I need from my database because I don't think it is properly normalized and because of limitations in my knowledge of relational database theory and mysql. I would appreciate input into the design of the board in general and in particular, ways that the database structure can be improved to facilitate efficient queries and help me develop this application and future application faster Business Logic The bulletin board will be used in the following way Posting bulletins and responses to bulletins Employees or 'users' in offices around the country will be able to post messages to the bulletin board.Bulletins must be posted to a location and categorised- i'll call these "bulletins". Users will be able to post any number of replies to any one bulletin and users will be able to reply to their own bulletin - i'll call these 'replies'. Rating bulletins and replies Users will be able to either 'like' or 'dislike' a bulletin or a reply and the total number of likes or dislikes will be shown for each bulletin or reply. Viewing the bulletin board and responses Bulletins can be displayed chronologically. Users can sort bulletins chronologically or chronologically by the latest reply to that bulletin(let me know if you need more explanation) When a particular bulletin is selected, replies to that bulletin will be displayed chronologically @PerformanceDBA - edited 10:34 est 28/12/10I have begun implementing the data model. I assume that the 6th data model is the physical model because it contains the associative tables. I am going to post any questions that I have below. I will put up a database dump once I am done. I will then put up a list of all the queries that I need to run on the database and begin writing them. I hope you had a good Christmas. I'm in Canada and there's snow! Implementation of Physical model

  Read the article

• Using an ORM with a database that has no defined relationships?

  - by Ahmad

  Consider a database(MSSQL 2005) that consists of 100+ tables which have primary keys defined to a certain degree. There are 'relationships' between tables, however these are not enforced with foreign key constraints. Consider the following simplified example of typical types of tables I am dealing with. The are clear relations between the User and City and Province tables. However, they key issues is the inconsistent data types in the tables and naming conventions. User: UserRowId [int] PK Name [varchar(50)] CityId [smallint] ProvinceRowId [bigint] City: CityRowId [bigint] PK CityDescription [varchar(100)] Province: ProvinceId [int] PK ProvinceDesc [varchar(50)] I am considering a rewrite of the application (in ASP.net MVC) that uses this data source as is similar in design to MVC storefront. However I am going through a proof of concept phase and this is one of the stumbling blocks I have come across. What are my options in terms of ORM choice that can be easily used and why? Should I even be considering an ORM? (The reason I ask this is that most explanations and tutorials all work with relatively cleanly designed existing databases, or newly created ones when compared to mine. I am thus having a very hard time trying to find a way forward with this problem) There is a huge amount of existing SQL queries, would a datamappper(eg IBatis.net) be more suitable since we could easily modify them to work and reuse the investment already made? I have found this question on SO which indicates to me that an ORM can be used - however I get the impression that this a question of mapping? Note: at the moment, the object model is not clearly defined as it was non-existent. The existing system pretty much did almost everything in SQL or consisted of overly complicated, and numerous queries to complete fucntionality. I am pretty much a noob and have zero experience around ORMs and MVC - so this an awesome learning curve I am on.

  Read the article

• Centralized Exception handling for Eclipse plug-in

  - by Svilen

  Hello, At first I thought this would be question often asked, however trying (and failing) to look up info on this proved me wrong. Is there a mechanism in Eclipse platform for centralized exception handling of exceptions? For example... You have plug-in project which connects to a DB and issues queries, results of which are used to populate some e.g. views. This is like the most common example ever. :) Queries are executed almost for any user action, from every UI control the plug-in provides. Most likely the DB Query API will have some specific to the DB SomeDBGeneralException declared as being thrown by it. That's OK, you can handle those according to whatever your software design is. But how about unchecked exceptions which are likely to occur, e.g. , when communication with DB suddenly breaks for some network related reason? What if in such case one would like to catch those exceptions in a central place and for example provide user friendly message to the user (rather than the low level communication protocol api messages) and even some possible actions the user could execute in order to deal with the specific problem? Thinking in Eclipse platform context, the question may be rephrased as "Is there an extension point like "org.eclipse.ExceptionHandler" which allows to declare exception handlers for specific (some kind of filtering support) exceptions giving a lot of flexibility with the actual handling?"

  Read the article

• active record relations – who needs it?

  - by M2_

  Well, I`m confused about rails queries. For example: Affiche belongs_to :place Place has_many :affiches We can do this now: @affiches = Affiche.all( :joins => :place ) or @affiches = Affiche.all( :include => :place ) and we will get a lot of extra SELECTs, if there are many affiches: Place Load (0.2ms) SELECT "places".* FROM "places" WHERE "places"."id" = 3 LIMIT 1 Place Load (0.3ms) SELECT "places".* FROM "places" WHERE "places"."id" = 3 LIMIT 1 Place Load (0.8ms) SELECT "places".* FROM "places" WHERE "places"."id" = 444 LIMIT 1 Place Load (1.0ms) SELECT "places".* FROM "places" WHERE "places"."id" = 222 LIMIT 1 ...and so on... And (sic!) with :joins used every SELECT is doubled! Technically we cloud just write like this: @affiches = Affiche.all( ) and the result is totally the same! (Because we have relations declared). The wayout of keeping all data in one query is removing the relations and writing a big string with "LEFT OUTER JOIN", but still there is a problem of grouping data in multy-dimentional array and a problem of similar column names, such as id. What is done wrong? Or what am I doing wrong? UPDATE: Well, i have that string Place Load (2.5ms) SELECT "places".* FROM "places" WHERE ("places"."id" IN (3,444,222,57,663,32,154,20)) and a list of selects one by one id. Strange, but I get these separate selects when I`m doing this in each scope: <%= link_to a.place.name, **a.place**( :id => a.place.friendly_id ) %> the marked a.place is the spot, that produces these extra queries.

  Read the article

• 'LINQ query plan' horribly inefficient but 'Query Analyser query plan' is perfect for same SQL!

  - by Simon_Weaver

  I have a LINQ to SQL query that generates the following SQL : exec sp_executesql N'SELECT COUNT(*) AS [value] FROM [dbo].[SessionVisit] AS [t0] WHERE ([t0].[VisitedStore] = @p0) AND (NOT ([t0].[Bot] = 1)) AND ([t0].[SessionDate] > @p1)',N'@p0 int,@p1 datetime', @p0=1,@p1='2010-02-15 01:24:00' (This is the actual SQL taken from SQL Profiler on SQL Server 2008.) The query plan generated when I run this SQL from within Query Analyser is perfect. It uses an index containing VisitedStore, Bot, SessionDate. The query returns instantly. However when I run this from C# (with LINQ) a different query plan is used that is so inefficient it doesn't even return in 60 seconds. This query plan is trying to do a key lookup on the clustered primary key which contains a couple million rows. It has no chance of returning. What I just can't understand though is that the EXACT same SQL is being run - either from within LINQ or from within Query Analyser yet the query plan is different. I've ran the two queries many many times and they're now running in isolation from any other queries. The date is DateTime.Now.AddDays(-7), but I've even hardcoded that date to eliminate caching problems. Is there anything i can change in LINQ to SQL to affect the query plan or try to debug this further? I'm very very confused!

  Read the article

• Django IntegrityError: foreign key violation upon delete

  - by Lukasz Korzybski

  I have Order and Shipment model. Shipment has a foreign key to Order. class Order(...): ... class Shipment() order = m.ForeignKey('Order') ... Now in one of my views I want do delete order object along with all related objects. So I invoke order.delete(). I have Django 1.0.4, PostgreSQL 8.4 and I use transaction middleware, so whole request is enclosed in single transaction. The problem is that upon order.delete() I get: ... File "/usr/local/lib/python2.6/dist-packages/django/db/backends/__init__.py", line 28, in _commit return self.connection.commit() IntegrityError: update or delete on table "main_order" violates foreign key constraint "main_shipment_order_id_fkey" on table "main_shipment" DETAIL: Key (id)=(45) is still referenced from table "main_shipment". I checked in connection.queries that proper queries are executed in proper order. First shipment is deleted, after that django executes delete on order row: {'time': '0.000', 'sql': 'DELETE FROM "main_shipment" WHERE "id" IN (17)'}, {'time': '0.000', 'sql': 'DELETE FROM "main_order" WHERE "id" IN (45)'} Foreign key have ON DELETE NO ACTION (default) and is initially deferred. I don't know why I get foreign key constraint violation. I also tried to register pre_delete signal and manually delete shipment objects before delete on order is called, but it resulted in the same error. I can change ON DELETE behaviour for this key in Postgres but it would be just a hack, I wonder if anyone has a better idea what's going on here. There is also a small detail, my Order model inherits from Cart model, so it actually doesn't have id field but cart_ptr_id and after DELETE on order is executed there is also DELETE on cart, but it seems unrelated? to the shipment-order problem so I simplified it in the example.

  Read the article

• mysql subquery strangely slow

  - by aviv

  I have a query to select from another sub-query select. While the two queries look almost the same the second query (in this sample) runs much slower: SELECT user.id ,user.first_name -- user.* FROM user WHERE user.id IN (SELECT ref_id FROM education WHERE ref_type='user' AND education.institute_id='58' AND education.institute_type='1' ); This query takes 1.2s Explain on this query results: id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY user index first_name 152 141192 Using where; Using index 2 DEPENDENT SUBQUERY education index_subquery ref_type,ref_id,institute_id,institute_type,ref_type_2 ref_id 4 func 1 Using where The second query: SELECT -- user.id -- user.first_name user.* FROM user WHERE user.id IN (SELECT ref_id FROM education WHERE ref_type='user' AND education.institute_id='58' AND education.institute_type='1' ); Takes 45sec to run, with explain: id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY user ALL 141192 Using where 2 DEPENDENT SUBQUERY education index_subquery ref_type,ref_id,institute_id,institute_type,ref_type_2 ref_id 4 func 1 Using where Why is it slower if i query only by index fields? Why both queries scans the full length of the user table? Any ideas how to improve? Thanks.

  Read the article

• How to write a good PHP database insert using an associative array

  - by Tom

  In PHP, I want to insert into a database using data contained in a associative array of field/value pairs. Example: $_fields = array('field1'=>'value1','field2'=>'value2','field3'=>'value3'); The resulting SQL insert should look as follows: INSERT INTO table (field1,field2,field3) VALUES ('value1','value2','value3'); I have come up with the following PHP one-liner: mysql_query("INSERT INTO table (".implode(',',array_keys($_fields)).") VALUES (".implode(',',array_values($_fields)).")"); It separates the keys and values of the the associative array and implodes to generate a comma-separated string . The problem is that it does not escape or quote the values that were inserted into the database. To illustrate the danger, Imagine if $_fields contained the following: $_fields = array('field1'=>"naustyvalue); drop table members; --"); The following SQL would be generated: INSERT INTO table (field1) VALUES (naustyvalue); drop table members; --; Luckily, multiple queries are not supported, nevertheless quoting and escaping are essential to prevent SQL injection vulnerabilities. How do you write your PHP Mysql Inserts? Note: PDO or mysqli prepared queries aren't currently an option for me because the codebase already uses mysql extensively - a change is planned but it'd take alot of resources to convert?

  Read the article

• select all values from a dimension for which there are facts in all other dimensions

  - by ideasculptor

  I've tried to simplify for the purposes of asking this question. Hopefully, this will be comprehensible. Basically, I have a fact table with a time dimension, another dimension, and a hierarchical dimension. For the purposes of the question, let's assume the hierarchical dimension is zip code and state. The other dimension is just descriptive. Let's call it 'customer' Let's assume there are 50 customers. I need to find the set of states for which there is at least one zip code in which EVERY customer has at least one fact row for each day in the time dimension. If a zip code has only 49 customers, I don't care about it. If even one of the 50 customers doesn't have a value for even 1 day in a zip code, I don't care about it. Finally, I also need to know which zip codes qualified the state for selection. Note, there is no requirement that every zip code have a full data set - only that at least one zip code does. I don't mind making multiple queries and doing some processing on the client side. This is a dataset that only needs to be generated once per day and can be cached. I don't even see a particularly clean way to do it with multiple queries short of simply brute-force iteration, and there are a heck of a lot of 'zip codes' in the data set (not actually zip codes, but the there are approximately 100,000 entries in the lower level of the hierarchy and several hundred in the top level, so zipcode-state is a reasonable analogy)

  Read the article

• PHP curl timing mismatch

  - by JonoB

  I am running a php script that: queries a local database to retrieve an amount executes a curl statement to update an external database with the above amount + x queries the local database again to insert a new row reflecting that the curl statement has been executed. One of the problems that I am having is that the curl statement takes 2-4 seconds to execute, so I have two different users from the same company running the same script at the same time, the execution time of the curl command can cause a mismatch in what should be updated in the external database. This is the because the curl statement has not yet returned from the first user...so the second user is working off incorrect figures. I am not sure of the best options here, but basically I need to prevent two or more curl statements being run at the same time. I thought of storing a value in the database that indicates that the curl statement is being executed at that time, and prevent any other curl statements being run until its completed. Once the first curl statement has been executed, then the database flag is updated and the next one can run. If this field is 'locked', then I could loop through the code and sleep for (5) seconds, and then check again if the flag has been reset. If after (3) loops, then reset the flag automatically (i've never seen the curl take longer than 5 seconds) and continue processing. Are there any other (more elegant) ways of approaching this?

  Read the article

• confusion about using types instead of gtts in oracle

  - by Omnipresent

  I am trying to convert queries like below to types so that I won't have to use GTT: insert into my_gtt_table_1 (house, lname, fname, MI, fullname, dob) (select house, lname, fname, MI, fullname, dob from (select 'REG' house, mbr_last_name lname, mbr_first_name fname, mbr_mi MI, mbr_first_name || mbr_mi || mbr_last_name fullname, mbr_dob dob from table_1 a, table_b where a.head = b.head and mbr_number = '01' and mbr_last_name = v_last_name) c above is just a sample but complex queries are bigger than this. the above is inside a stored procedure. So to avoid the gtt (my_gtt_table_1). I did the following: create or replace type lname_row as object ( house varchar2(30) lname varchar2(30), fname varchar2(30), MI char(1), fullname VARCHAR2(63), dob DATE ) create or replace type lname_exact as table of lname_row Now in the SP: type lname_exact is table of <what_table_should_i_put_here>%rowtype; tab_a_recs lname_exact; In the above I am not sure what table to put as my query has nested subqueries. query in the SP: (I am trying this for sample purpose to see if it works) select lname_row('', '', '', '', '', '', sysdate) bulk collect into tab_a_recs from table_1; I am getting errors like : ORA-00913: too many values I am really confused and stuck with this :(

  Read the article

• MSMQ - Message Queue Abstraction and Pattern

  - by Maxim Gershkovich

  Hi All, Let me define the problem first and why a messagequeue has been chosen. I have a datalayer that will be transactional and EXTREMELY insert heavy and rather then attempt to deal with these issues when they occur I am hoping to implement my application from the ground up with this in mind. I have decided to tackle this problem by using the Microsoft Message Queue and perform inserts as time permits asynchronously. However I quickly ran into a problem. Certain inserts that I perform may need to be recalled (ie: retrieved) immediately (imagine this is for POS system and what happens if you need to recall the last transaction - one that still hasn’t been inserted). The way I decided to tackle this problem is by abstracting the MessageQueue and combining it in my data access layer thereby creating the illusion of a single set of data being returned to the user of the datalayer (I have considered the other issues that occur in such a scenario (ie: essentially dirty reads and such) and have concluded for my purposes I can control these issues). However this is where things get a little nasty... I’ve worked out how to get the messages back and such (trivial enough problem) but where I am stuck is; how do I create a generic (or at least somewhat generic) way of querying my message queue? One where I can minimize the duplication between the SQL queries and MessageQueue queries. I have considered using LINQ (but have very limited understanding of the technology) and have also attempted an implementation with Predicates which so far is pretty smelly. Are there any patterns for such a problem that I can utilize? Am I going about this the wrong way? Does anyone have an of their own ideas about how I can tackle this problem? Does anyone even understand what I am talking about? :-) Any and ALL input would be highly appreciated and seriously considered… Thanks again.

  Read the article

• Sql Compact and __sysobjects

  - by Scott Wisniewski

  I have some SQL Compact queries that create tables inside of transaction. This is mainly because I need to simulate temporary tables, which SQL Compact does not support. I do this by creating a real table, and then dropping it at the end of the transaction. This mostly works. Sometimes, however, when creating the tables Sql Compact will try to acquire PAGE level locks on the __sysobjects table. If there are several concurrent queries running that create "temp" tables, the attempt to acquire a page lock can result in a dead lock followed by a SqlLockTimeout exception. For normal tables I could fix this using a "with (rowlock)" hint. However, because I'm not writing the query to insert into __sysobjets (SQL server does that in response to "create table") I can't do this. Does anyone know of a way I could get around this? I've thought about pulling the table creation out of the transaction, but that opens up the possibility of phantom temporary tables that I'd then need to clean up regularly. Ideally I'd like to avoid that if possible.

  Read the article

• MySQL 5.5.8 Gets Periodic Lag

  - by CYREX

  Am using MySQL 5.5.8 on an Ubuntu system and every X amount of time it creates a huge lag that lasts a couple of seconds. Then all goes back to normal until the next lag. The time period varies but it looks like it happen periodically. Am using InnoDB. It is like hiccups in the MySQL. What could be creating this sort of periodic problem. Do not have any cron jobs or process running every time the X period happens. The X period could be between 30 minutes to 2 hours. So for example it could happen every 30 minutes for the next 12 hours or it could happen every 2 hours for the next 8 hours. key_buffer_size = 256M max_allowed_packet = 1M table_cache = 1024 table_open_cache = 1024 sort_buffer_size = 2M read_buffer_size = 2M read_rnd_buffer_size = 4M myisam_sort_buffer_size = 32M thread_cache_size = 128 query_cache_size= 128M log-slow-queries = slow.log long_query_time = 5 log-queries-not-using-indexes # Try number of CPU's*2 for thread_concurrency thread_concurrency = 4 max_connections=512 #innodb_data_file_path = ibdata1:10M:autoextend #innodb_log_group_home_dir = /usr/local/mysql/data # You can set .._buffer_pool_size up to 50 - 80 % # of RAM but beware of setting memory usage too high innodb_buffer_pool_size = 1G #innodb_additional_mem_pool_size = 20M # Set .._log_file_size to 25 % of buffer pool size #innodb_log_file_size = 64M #innodb_log_buffer_size = 8M #innodb_flush_log_at_trx_commit = 0 #innodb_lock_wait_timeout = 50 [mysqldump] quick max_allowed_packet = 16M [myisamchk] key_buffer_size = 64M sort_buffer_size = 64M read_buffer = 2M write_buffer = 2M There are about 200+ tables divided in 3 databases. The most written too is in InnoDB. The other ones are more read. Several of the tables in the InnoDB have more than 2 million records. The other databases top at about 400 thousand records and do not change so often. The PC is a Core 2 Duo 8400 with 4GB RAM, 32Bit Ubuntu.

  Read the article

• What database strategy to choose for a large web application

  - by Snoopy

  I have to rewrite a large database application, running on 32 servers. The hardware is up to date, each machine has two quad core Xeon and 32 GByte RAM. The database is multi-tenant, each customer has his own file, around 5 to 10 GByte each. I run around 50 databases on this hardware. The app is open to the web, so I have no control on the load. There are no really complex queries, so SQL is not required if there is a better solution. The databases get updated via FTP every day at midnight. The database is read-only. C# is my favourite language and I want to use ASP.NET MVC. I thought about the following options: Use two big SQL servers running SQL Server 2012 to serve the 32 servers with data. On the 32 servers running IIS hosting providing REST services. Denormalize the database and use Redis on each webserver. Use booksleeve as a Redis client. Use a combination of SQL Server and Redis Use SQL Server 2012 together with Hadoop Use Hadoop without SQL Server What is the best way for a read-only database, to get the best performance without loosing maintainability? Does Map-Reduce make sense at all in such a scenario? The reason for the rewrite is, the old app written in C++ with ISAM technology is too slow, the interfaces are old fashioned and not nice to use from an website, especially when using ajax. The app uses a relational datamodel with many tables, but it is possible to write one accerlerator table where all queries can be performed on, and all other information from the other tables are possible by a simple key lookup.

  Read the article

• Can one connection get details of another? Or, how can I get the most detailed pending transaction

  - by bob-the-destroyer

  Is there a Mysql statement which provides full details of any other open connection or user? For this particular case, on myisam tables specifically. Looking at Mysql's SHOW TABLE STATUS documentation, it's missing some very important information for my purpose. For example: remote odbc connection one is inserting several thousand records, which due to a slow connection speed can take up to an hour. Tcp connection two, using PHP on the server's localhost, is running select queries with aggregate functions on that data. Before allowing connection two to run those queries, I'd like connection two to first check to make sure there's no pending inserts on any other connection on those specific tables so it can instead wait until all data is available. If the table is currently being written to, I'd like to spit back to the user of connection two an approximation of how much longer to wait based on the number of pending inserts. Ideally by table, I'd like to get back using a query the timestamp when connection one began the write, total inserts left to be done, and total inserts already completed. Instead of insert counts, even knowing number of bytes written and left to write would work just fine here. Obviously since connection two is a tcp connection via a PHP script, all I can really use in that script is some sort of query. I suppose if I have to, since it is on localhost, I can exec() it if the only way is by a mysql command line option that outputs this info, but I'd rather not. I suppose I could simply update a custom-made transaction log before and after this massive insert task which the PHP script can check, but hopefully there's already a built-in Mysql feature I can take advantage of.

  Read the article

• Is there a way to automatically load navigational property using the .NET Entity Framework?

  - by René Wolferink

  Stepping away more and more from writing SQL for my applications, I decided to give the Entity Framework a try. However, I've run into something I believe is causing me to write more code than I think is strictly necessary. When I accessed some navigational properties, I discovered that all many-to-one relations (simple references) were null and all one-to-many and many-to-many relations (EntityCollections) were empty. For example: I have a User with a reference to a Group. When I have retieved a User, by using a simple select-by-id, the Group property is null. If I want to access the Group I have to manually load it (using User.GroupReference.Load()). So I added a GetGroup() method in User which checks whether the Group is loaded already and, if not, does so and then returns the Group. Now this will result in a lot of highly similar methods for all navigational properties. And it all results in the navigational properties not being used, only my custom-made Get"PropertyName"() method's are now being used. I don't want to expand my queries (linq to entities) to immediately load all these properties, because it's not always known at first what is needed. And besides, it would cause a lot of queries to have to be made. Is there a way to configure the Entity Framework to load these objects when they happen to not be present? So when I access User.Group and the group is not loaded yet, it is loaded automatically? Or am I stuck using my own Get"PropertyName"() method's as long as I'm trying to load objects only on demand (or "just-in-time")? Some extra info: I'm using VS2008 SP1 with .NET 3.5 SP1. The Entity Framework I'm using is the one that got shipped with it.

  Read the article

• MySQL: How to pull information from multiple tables based on information in other tables?

  - by Greg

  Ok, I have 5 tables which I need to pull information from based on one variable. gameinfo id | name | platforminfoid gamerinfo id | name | contact | tag platforminfo id | name | abbreviation rosterinfo id | name | gameinfoid rosters id | gamerinfoid | rosterinfoid The 1 variable would be gamerinfo.id, which would then pull all relevant data from gamerinfo, which would pull all relevant data from rosters, which would pull all relevant data from rosterinfo, which would pull all relevant data from gameinfo, which would then pull all relevant data from platforminfo. Basically it breaks down like this: gamerinfo contains the gamers basic information. rosterinfo contains basic information about the rosters (ie name and the game the roster is aimed towards) rosters contains the actual link from the gamer to the different rosters (gamers can be on multiple rosters) gameinfo contains basic information about the games (ie name and platform) platform info contains information about the different platforms the games are played on (it is possible for a game to be played on multiple platforms) I am pretty new to SQL queries involving JOINs and UNIONs and such, usually I would just break it up into multiple queries but I thought there has to be a better way, so after looking around the net, I couldn't find (or maybe I just couldn't understand what I was looking at) what I was looking for. If anyone can point me in the right direction I would be most grateful.

  Read the article

• How to optimize a postgreSQL server for a "write once, read many"-type infrastructure ?

  - by mhu

  Greetings, I am working on a piece of software that logs entries (and related tagging) in a PostgreSQL database for storage and retrieval. We never update any data once it has been inserted; we might remove it when the entry gets too old, but this is done at most once a day. Stored entries can be retrieved by users. The insertion of new entries can happen rather fast and regularly, thus the database will commonly hold several millions elements. The tables used are pretty simple : one table for ids, raw content and insertion date; and one table storing tags and their values associated to an id. User search mostly concern tags values, so SELECTs usually consist of JOIN queries on ids on the two tables. To sum it up : 2 tables Lots of INSERT no UPDATE some DELETE, once a day at most some user-generated SELECT with JOIN huge data set What would an optimal server configuration (software and hardware, I assume for example that RAID10 could help) be for my PostgreSQL server, given these requirements ? By optimal, I mean one that allows SELECT queries taking a reasonably little amount of time. I can provide more information about the current setup (like tables, indexes ...) if needed.

  Read the article

• PHP Check slave status without mysql_connect timeout issues

  - by Jonathon

  I have a web-app that has a master mysql db and four slave dbs. I want to handle all (or almost all) read-only (SELECT) queries from the slaves. Our load-balancer sends the user to one of the slave machines automatically, since they are also running Apache/PHP and serving webpages. I am using an include file to setup the connection to the databases, such as: //for master server (i.e. - UPDATE/INSERT/DELETE statements) $Host = "10.0.0.x"; $User = "xx"; $Password = "xx"; $Link = mysql_connect( $Host, $User, $Password ); if( !$Link ) ) { die( "Master database is currently unavailable. Please try again later." ); } //this connection can be used for READ-ONLY (i.e. - SELECT statements) on the localhost $Host_Local = "localhost"; $User_Local = "xx"; $Password_Local = "xx"; $Link_Local = mysql_connect( $Host_Local, $User_Local, $Password_Local ); //fail back to master if slave db is down if( !$Link_Local ) ) { $Link_Local = mysql_connect( $Host, $User, $Password ); } I then use $Link for all update queries and $Link_Local as the connection for SELECT statements. Everything works fine until the slave server database goes down. If the local db is down, the $Link_Local = mysql_connect() call takes at least 30 seconds before it gives up on trying to connect to the localhost and returns back to the script. This causes a huge backlog of page serves and basically shuts down the system (due to the extremely slow response time). Does anyone know of a better way to handle connections to slave servers via PHP? Or, is there some kind of timeout function that could be used to stop the mysql_connect call after 2-3 seconds? Thanks for the help. I searched the other mysql_connect threads, but didn't see any that addressed this issue.

  Read the article

• how to write this query using joins?

  - by aquero

  Hi, i have a table campaign which has details of campaign mails sent. campaign_table: campaign_id campaign_name flag 1 test1 1 2 test2 1 3 test3 0 another table campaign activity which has details of campaign activities. campaign_activity: campaign_id is_clicked is_opened 1 0 1 1 1 0 2 0 1 2 1 0 I want to get all campaigns with flag value 3 and the number of is_clicked columns with value 1 and number of columns with is_opened value 1 in a single query. ie. campaign_id campaign_name numberofclicks numberofopens 1 test1 1 1 2 test2 1 1 I did this using sub-query with the query: select c.campaign_id,c.campaign_name, (SELECT count(campaign_id) from campaign_activity WHERE campaign_id=c.id AND is_clicked=1) as numberofclicks, (SELECT count(campaign_id) from campaign_activity WHERE campaign_id=c.id AND is_clicked=1) as numberofopens FROM campaign c WHERE c.flag=1 But people say that using sub-queries are not a good coding convention and you have to use join instead of sub-queries. But i don't know how to get the same result using join. I consulted with some of my colleagues and they are saying that its not possible to use join in this situation. Is it possible to get the same result using joins? if yes, please tell me how.

  Read the article

• MySQL: Limit rows linked to each joined row

  - by SolidSnakeGTI

  Hello, Specifications: MySQL 4.1+ I've certain situation that requires certain result set from MySQL query, let's see the current query first & then ask my question: SELECT thread.dateline AS tdateline, post.dateline AS pdateline, MIN(post.dateline) FROM thread AS thread LEFT JOIN post AS post ON(thread.threadid = post.threadid) LEFT JOIN forum AS forum ON(thread.forumid = forum.forumid) WHERE post.postid != thread.firstpostid AND thread.open = 1 AND thread.visible = 1 AND thread.replycount >= 1 AND post.visible = 1 AND (forum.options & 1) AND (forum.options & 2) AND (forum.options & 4) AND forum.forumid IN(1,2,3) GROUP BY post.threadid ORDER BY tdateline DESC, pdateline ASC As you can see, mainly I need to select dateline of threads from 'thread' table, in addition to dateline of the second post of each thread, that's all under the conditions you see in the WHERE CLAUSE. Since each thread has many posts, and I need only one result per thread, I've used GROUP BY CLAUSE for that purpose. This query will return only one post's dateline with it's related unique thread. My questions are: How to limit returned threads per each forum!? Suppose I need only 5 threads -as a maximum- to be returned for each forum declared in the WHERE CLAUSE 'forum.forumid IN(1,2,3)', how can this be achieved. Is there any recommendations for optimizing this query (of course after solving the first point)? Notes: I prefer not to use sub-queries, but if it's the only solution available I'll accept it. Double queries not recommended. I'm sure there's a smart solution for this situation. Appreciated advice in advance :)

  Read the article

• SELECT set of most recent id, amount FROM table, where id occurs many times

  - by Jon Cram

  I have a table recording the amount of data transferred by a given service on a given date. One record is entered daily for a given service. I'd like to be able to retrieve the most recent amount for a set of services. Example data set: serviceId | amount | date ------------------------------- 1 | 8 | 2010-04-12 2 | 11 | 2010-04-12 2 | 14 | 2010-04-11 3 | 9 | 2010-04-11 1 | 6 | 2010-04-10 2 | 5 | 2010-04-10 3 | 22 | 2010-04-10 4 | 17 | 2010-04-19 Desired response (service ids 1,2,3): serviceId | amount | date ------------------------------- 1 | 8 | 2010-04-12 2 | 11 | 2010-04-12 3 | 9 | 2010-04-11 Desired response (service ids 2, 4): serviceId | amount | date ------------------------------- 2 | 11 | 2010-04-12 4 | 17 | 2010-04-19 This retrieves the equivalent as running the following once per serviceId: SELECT serviceId, amount, date FROM table WHERE serviceId = <given serviceId> ORDER BY date DESC LIMIT 0,1 I understand how I can retrieve the data I want in X queries. I'm interested to see how I can retrieve the same data using either a single query or at the very least less than X queries. I'm very interested to see what might be the most efficient approach. The table currently contains 28809 records. I appreciate that there are other questions that cover selecting the most recent set of records. I have examined three such questions but have been unable to apply the solutions to my problem.

  Read the article

< Previous Page | 65 66 67 68 69 70 71 72 73 74 75 76  | Next Page >