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  • Two models, one STI and a Validation

    - by keruilin
    Let's say I have two tables -- Products and Orders. For the sake of simplicity assume that only one product can be purchased at a time so there is no join table like order_items. So the relationship is that Product has many orders, and Order belongs to product. Therefore, product_id is a fk in the Order table. The product table is STI -- with the subclasses being A, B, C. When the user orders subclass Product C, two special validations must be checked on the Order model fields order_details and order_status. These two fields can be nil for all other Product subclasses (ie A and B). In other words, no validation needs to run for these two fields when a user purchases A and B. My question is: How do I write validations (perhaps custom?) in the Order model so that the Order model knows to only run the validations for the two fields -- order_details and order_status -- when Product subclass C is being saved to the orders table?

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  • Will SQL Server Partitioning increase performance without changing filegroups

    - by Tom
    Scenario I have a 10 million row table. I partition it into 10 partitions, which results in 1 million rows per partition but I do not do anything else (like move the partitions to different file groups or spindles) Will I see a performance increase? Is this in effect like creating 10 smaller tables? If I have queries that perform key lookups or scans, will the performance increase as if they were operating against a much smaller table? I'm trying to understand how partitioning is different from just having a well indexed table, and where it can be used to improve performance. Would a better scenario be to move the old data (using partition switching) out of the primary table to a read only archive table? Is having a table with a 1 million row partition and a 9 million row partition analagous (performance wise) to moving the 9 million rows to another table and leaving only 1 million rows in the original table?

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  • username and password check linq query in c#

    - by b0x0rz
    this linq query var users = from u in context.Users where u.UserEMailAdresses.Any(e1 => e1.EMailAddress == userEMail) && u.UserPasswords.Any(e2 => e2.PasswordSaltedHash == passwordSaltedHash) select u; return users.Count(); returns: 1 even when there is nothing in password table. how come? what i am trying to do is get the values of email and passwordHash from two separate tables (UserEMailAddresses and UserPasswords) linked via foreign keys to the third table (Users). it should be simple - checking if email and password mach from form to database. but it is not working for me. i get 1 (for count) even when there are NO entries in the UserPasswords table. is the linq query above completely wrong, or...?

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  • How to create a view of table that contains a timestamp column?

    - by Matt Faus
    This question is an extension of a previous one I have asked. I have a table (2014_05_31_transformed.Video) with a schema that looks like this. I have put up the JSON returned by the BigQuery API describing it's schema in this gist. I am trying to create a view against this table with an API call that looks like this: { 'view': { 'query': u 'SELECT deleted_mod_time FROM [2014_05_31_transformed.Video]' }, 'tableReference': { 'datasetId': 'latest_transformed', 'tableId': u 'Video', 'projectId': 'redacted' } } But, the BigQuery API is returning this error: HttpError: https://www.googleapis.com/bigquery/v2/projects/124072386181/datasets/latest_transformed/tables?alt=json returned "Invalid field name "deleted_mod_time.usec". Fields must contain only letters, numbers, and underscores, start with a letter or underscore, and be at most 128 characters long." The schema that the BigQuery API does not make any distinction between a TIMESTAMP data type and a regular nullable INTEGER data type, so I can't think of a way to programmatically correct this problem. Is there anything I can do, or is this a bug with BigQuery's view implementation?

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  • NoSql Crash Course/Tutorial

    - by Chris Thompson
    Hi all, I've seen NoSQL pop up quite a bit on SO and I have a solid understanding of why you would use it (from here, Wikipedia, etc). This could be due to the lack of concrete and uniform definition of what it is (more of a paradigm than concrete implementation), but I'm struggling to wrap my head around how I would go about designing a system that would use it or how I would implement it in my system. I'm really stuck in a relational-db mindset thinking of things in terms of tables and joins... At any rate, does anybody know of a crash course/tutorial on a system that would use it (kind of a "hello world" for a NoSQL-based system) or a tutorial that takes an existing "Hello World" app based on SQL and converts it to NoSQL (not necessarily in code, but just a high-level explanation). I see this having one solid answer, but if you guys feel like it should be community wiki, I'll be happy to change it. Thanks! Chris

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  • Insert query results into table in ms access 2010

    - by CodeMed
    I need to transform data from one schema into another in an MS Access database. This involves writing queries to select data from the old schema and then inserting the results of the queries into tables in the new schema. The below is an example of what I am trying to do. The SELECT component of the below works fine, but the INSERT component does not work. Can someone show me how to fix the below so that it effectively inserts the results of the SELECT statement into the destination table? INSERT INTO CompaniesTable (CompanyName) VALUES ( SELECT DISTINCT IIF(a.FIRM_NAME IS NULL, b.SUBACCOUNT_COMPANY_NAME, a.FIRM_NAME) AS CompanyName FROM (SELECT ContactID, FIRM_NAME, SUBACCOUNT_COMPANY_NAME FROM qrySummaryData) AS a LEFT JOIN (SELECT ContactID, FIRM_NAME, SUBACCOUNT_COMPANY_NAME FROM qrySummaryData) AS b ON a.ContactID = b.ContactID ); The definition of the target table (CompaniesTable) is: CompanyID Autonumber CompanyName Text Description Text WebSite Text Email Text TypeNumber Number

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  • Sphinx non-fulltext, integer only search

    - by James
    Hello guys, I've got a few tables that literally only hold integers, no "words" and for some reason Sphinx is unable to hold this data in it's library. Just returns "0 bytes" errors for these indexes. Is it possible to do this? If so, how? Below is an example from my Sphinx.conf for one that fails. source track { type = mysql sql_host = host sql_user = user sql_pass = pass sql_db = db sql_port = port sql_query = SELECT id, user, time FROM track; sql_attr_uint = user sql_attr_uint = time sql_query_info = SELECT * FROM track WHERE id=$id } index track { source = track path = /var/lib/sphinx/track docinfo = extern charset_type = utf-8 min_prefix_len = 1 enable_star = 1 }

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  • joins- how to pass the parameter in stored procedure to execute a join query

    - by Ranjana
    i have used joins to get datas from two tables under comman name. as SELECT userValidity.UserName, userValidity.ValidFrom,userValidity.ValidUpTo,userValidity.TotalPoints, persons.SenderID FROM userValidity INNER JOIN persons ON userValidity.Username=tbl_persons.Username but i need to execute this query with oly the username which i pass as parameter in stored procedure.. how to pass the username in stored procedure in this joins. alter procedure GetNameIDUserInformation ( @user varchar(max) ) as begin SELECT userValidity.UserName, userValidity.ValidFrom,userValidity.ValidUpTo,userValidity.TotalPoints, persons.SenderID FROM userValidity INNER JOIN persons ON userValidity.Username=tbl_persons.Username end in this SP, where i have to pass the user parameter to get the single row of my user record

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  • Can an Excel VBA UDF called from the worksheet ever be passed an instance of any Excel VBA object mo

    - by jtolle
    I'm 99% sure that the answer is "no", but I'm wondering if someone who is 100% sure can say so. Consider a VBA UDF: Public Function f(x) End Function When you call this from the worksheet, 'x' will be a number, string, boolean, error, array, or object of type 'Range'. Can it ever be, say, an instance of 'Chart', 'ListObject', or any other Excel-VBA object model class? (The question arose from me moving to Excel 2007 and playing with Tables, and wondering if I could write UDFs that accept them as parameters instead of Ranges. The answer to that seems to be no, but then I realized I didn't know for sure in general.)

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  • Query to return internal details about stored function in SQL Server database

    - by Anthony
    I have been given access to a SQL Server database that is currently used by 3rd party app. As such, I don't have any documentation on how that application stores the data or how it retrieves it. I can figure a few things out based on the names of various tables and the parameters that the user-defined functions takes and returns, but I'm still getting errors at every other turn. I was thinking that it would be really helpful if I could see what the stored functions were doing with the parameters given to return the output. Right now all I've been able to figure out is how to query for the input parameters and the output columns. Is there any built-in information_schema table that will expose what the function is doing between input and output?

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  • Database indexes - what should they be

    - by WebweaverD
    Most of my database tables have a clear unique index through which lookups are done 90% of the time but I am a bit unsure on this one - I have a table which keeps track of user rating totals for items in my database, I now want to add another table, to track individual ratings with an ip address column to make sure no one can rate something twice. Since I can see this becoming a big, high use table it is important to optimize it correctly. (MYSQL table) This table will have the following fields: rating_id(always - unique), item_id (always - not unique), user_id (optional - not unique), ip_address (always - not unique), rating_value(always - not unique), has_review(bool) Now I envisions 90% the queries going something like this: When a user rates something - select where item_id = x and ip_address = y, (if rows = 0) insert rating When in user account pages - select where ip_address = x or username = y Now none of the fields searched on are unique, can I still use them as indexes (for example item _id and ip_address), can I have two indexes and will this still improve performance over a non indexed table?

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  • Useful ways for multilanguage navigation and static content on your site?

    - by vitto
    Hi, I have a big site running under Apache and PHP and in few mounths I should consider to add some different language version of it, but I'm not sure about the right way (or ways). My problem it isn't the user data, because I can use db tables with different languages (en, de, it, etc.) so I want concentrate my answer on navigation and static content. For now I can't use gettext because I don't have a dedicated server and I can't reboot it every time I want, but surely will be a future choice. So my main problems are these: In the site, I have classical XHTML elements like the menus, lists, div and various static texts in various pages (should be perferct for gettext, but I need a alternative) The other part of the sites has XHTML elements which are dynamically created via AJAX and jQuery, and here I haven't any idea of what can I do... So does exists some example I can see in some link to solve it (or some useful tecnique)?

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  • MS Sql Full-text search vs. LIKE expression

    - by Marks
    Hi. I'm currently looking for a way to search a big database (500MB - 10GB or more on 10 tables) with a lot of different fields(nvarchars and bigints). Many of the fields, that should be searched are not in the same table. An example: A search for '5124 Peter' should return all items, that ... have an ID with 5124 in it, have 'Peter' in the title or description have item type id with 5124 in it created by a user named 'peter' or a user whose id has 5124 in it created by a user with '5124' or 'peter' in his street address. How should i do the search? I read that the full-text search of MS-Sql is a lot more performant than a query with the LIKE keyword and i think the syntax is more clear, but i think it cant search on bigint(id) values and i read it has performance problems with indexing and therefore slows down inserts to the DB. In my project there will be more inserting than reading, so this could be a matter. Thanks in advance, Marks

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  • Django : mysql : 1045, "Access denied for user

    - by PlanetUnknown
    I have the whole setup working for months on my local computer. I'm installing on a remote site now. Created a fresh mysql DB, and created a new user ("someuser") and gave it complete grants, like so - GRANT ALL PRIVILEGES ON . TO 'someuser'@'localhost' IDENTIFIED BY 'somepassword' WITH GRANT OPTION; I have sync'd the db, using "python manage.py syncdb" and the correct tables were created. My settings.py has this same user. But when I try to login a user through the application, and it hits the DB, I see the following in the logs - (1045, "Access denied for user 'someuser'@'localhost' (using password: YES)") I logged in through mysql (installed on the same box as django) and checked the grants and it correctly shows - Grants for djangouser@localhost GRANT ALL PRIVILEGES ON * . * TO 'someuser'@'localhost' IDENTIFIED BY PASSWORD '*thesaltedpasswordOverHere' WITH GRANT OPTION I don't want to use the root user/password for django, since it doesn't seem the correct way. Any pointers as to what might be wrong ?

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  • MySQL - are FK's useful / viable in a web app?

    - by yoda
    Hi all, I've encountered this discussion related to FK's and web applications. Basically some people say that FK's in web applications doesn't represent a real improvement and can even make the application slower in some cases. What do you guys think, what's your experience? -- A quote from Heikki Tuuri, creator of InnoDB engine, founder and CEO of Innobase: InnoDB checks foreign keys as soon as a row is updated, no batching is performed or checks delayed till transaction commit Foreign keys are often serious performance overhead, but help maintain data consistency Foreign Keys increase amount of row level locking done and can make it spread to a lot of tables besides the ones directly updated

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  • Comparing COUNT values within a query?

    - by outsyncof
    I have the following tables in a relation: person(ssn,sex) employment(ssn,workweeksperyear) assume ssn is a key. My assignment was to do this: Given as input the number of weeks per year a person has worked, determine whether there are more males than females who work more weeks than the input value. SELECT COUNT(sex) AS NumMales FROM person WHERE sex = 'Male' AND ssn IN (SELECT ssn FROM employment WHERE workweeksperyear > 48); The above query gets me the number of males for an input value and I could do the same for number of females but how do I compare the 2 results? Any help will be greatly appreciated!

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  • Preview result of update/insert query whithout comitting changes to database in MySQL?

    - by Camsoft
    I am writing a script to import CSV files into existing tables within my database. I decided to do the insert/update operations myself using PHP and INSERT/UPDATE statements, and not use MySQL's LOAD INFILE command, I have good reasons for this. What I would like to do is emulate the insert/update operations and display the results to the user, and then give them the option of confirming that this is OK, and then committing the changes to the database. I'm using InnoDB database engine with support for transactions. Not sure if this helps but was thinking down the line of insert/update, query data, display to user, then either commit or rollback transaction? Any advise would be appreciated.

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  • SQL Server ORDER BY/WHERE with nested select

    - by Echilon
    I'm trying to get SQL Server to order by a column from a nested select. I know this isn't the best way of doing this but it needs to be done. I have two tables, Bookings and BookingItems. BookingItems contains StartDate and EndDate fields, and there can be multiple BookingItems on a Booking. I need to find the earliest startdate and latest end date from BookingItems, then filter and sort by these values. I've tried with a nested select, but when I try to use one of the selected columns in a WHERE or ORDER BY, I get an "Invalid Column Name". SELECT b.*, (SELECT COUNT(*) FROM bookingitems i WHERE b.BookingID = i.BookingID) AS TotalRooms, (SELECT MIN(i.StartDate) FROM bookingitems i WHERE b.BookingID = i.BookingID) AS StartDate, (SELECT MAX(i.EndDate) FROM bookingitems i WHERE b.BookingID = i.BookingID) AS EndDate FROM bookings b LEFT JOIN customers c ON b.CustomerID = c.CustomerID WHERE StartDate >= '2010-01-01' Am I missing something about SQL ordering? I'm using SQL Server 2008.

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  • MySQL indexes: how do they work?

    - by bob-the-destroyer
    I'm a complete newbie with MySQL indexes. I have several MyISAM tables on MySQL 5.0x having utf8 charsets and collations with 100k+ records each. The primary keys are generally integer. Many columns on each table may have duplicate values. I need to quickly count, sum, average, or otherwise perform custom calculations on any number of fields in each table or joined on any number of others. I found this page giving an overview of MySQL index usage: http://dev.mysql.com/doc/refman/5.0/en/mysql-indexes.html, but I'm still not sure I'm using indexes right. Just when I think I've made the perfect index out of a collection of fields I want to calculate against, I get the "index must be under 1000 bytes" error. Can anyone explain how to most efficiently create and use indexes to speed up queries? Caveat: upgrading Mysql is not possible in this case. Using Navicat Light for db administration, but this app isn't required.

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  • Entity Framework doesn't like 0..1 to * relationships.

    - by Orion Adrian
    I have a database framework where I have two tables. The first table has a single column that is an identity and primary key. The second table contains two columns. One is a nvarchar primary key and the other is a nullable foreign key to the first table. On the default import of the database I get the following error: Condition cannot be specified for Column member 'ForeignKeyId' because it is marked with a 'Computed' or 'Identity' StoreGeneratedPattern. where ForeignKeyId is the second foreign key reference in the second table. Is this just something the entity model doesn't do? Or am I missing something?

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  • Virtual Function Implementation

    - by Gokul
    Hi, I have kept hearing this statement. Switch..Case is Evil for code maintenance, but it provides better performance(since compiler can inline stuffs etc..). Virtual functions are very good for code maintenance, but they incur a performance penalty of two pointer indirections. Say i have a base class with 2 subclasses(X and Y) and one virtual function, so there will be two virtual tables. The object has a pointer, based on which it will choose a virtual table. So for the compiler, it is more like switch( object's function ptr ) { case 0x....: X->call(); break; case 0x....: Y->call(); }; So why should virtual function cost more, if it can get implemented this way, as the compiler can do the same in-lining and other stuff here. Or explain me, why is it decided not to implement the virtual function execution in this way? Thanks, Gokul.

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  • Freebase Query with "JOINS"

    - by codemonkey
    ... Yeah, yeah, I know traditional joins don't exist. I actually like the freebase query methodology in theory, just having a little trouble getting it to actually work for me : ) Anyone have a dumb-simple example of getting Freebase data via MQL that pulls from two different "tables"? In particular, I'm trying to get automotive data... so for example, pulling fields from both /automotive/model_year and /automotive/trim_year. I've read the documentation (for hours actually). There's a distinct possibility that I'm looking right at such an example somewhere and just not seeing it because my OLTP brain just doesn't comprehend what it's seeing. * Note * ... that the two "types" I'm working with above are siblings, not parent/child. Does freebase even allow joining data between sibling nodes... I see examples of queries pulling from parent/child, but not from siblings I don't think (or I've overlooked them).

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  • Using a table-alias in Kohana queries?

    - by Aristotle
    I'm trying to run a simple query with $this->db in Kohana, but am running into some syntax issues when I try to use an alias for a table within my query: $result = $this->db ->select("ci.chapter_id, ci.book_id, ci.chapter_heading, ci.chapter_number") ->from("chapter_info ci") ->where(array("ci.chapter_number" => $chapter, "ci.book_id" => $book)) ->get(); It seems to me that this should work just fine. I'm stating that "chapter_info" ought to be known as "ci," yet this isn't taking for some reason. The error is pretty straight-forward: There was an SQL error: Table 'gb_data.chapter_info ci' doesn't exist - SELECT `ci`.`chapter_id`, `ci`.`book_id`, `ci`.`chapter_heading`, `ci`.`chapter_number` FROM (`chapter_info ci`) WHERE `ci`.`chapter_number` = 1 AND `ci`.`book_id` = 1 If I use the full table name, rather than an alias, I get the expected results without error. This requires me to write much more verbose queries, which isn't ideal. Is there some way to use shorter names for tables within Kohana's query-builder?

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  • MySQL query killing my server

    - by Webnet
    Looking at this query there's got to be something bogging it down that I'm not noticing. I ran it for 7 minutes and it only updated 2 rows. //set product count for makes $tru->query->run(array( 'name' => 'get-make-list', 'sql' => 'SELECT id, name FROM vehicle_make', 'connection' => 'core' )); while($tempMake = $tru->query->getArray('get-make-list')) { $tru->query->run(array( 'name' => 'update-product-count', 'sql' => 'UPDATE vehicle_make SET product_count = ( SELECT COUNT(product_id) FROM taxonomy_master WHERE v_id IN ( SELECT id FROM vehicle_catalog WHERE make_id = '.$tempMake['id'].' ) ) WHERE id = '.$tempMake['id'], 'connection' => 'core' )); } I'm sure this query can be optimized to perform better, but I can't think of how to do it. vehicle_make = 45 rows taxonomy_master = 11,223 rows vehicle_catalog = 5,108 rows All tables have appropriate indexes

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  • How to optimise MySQL query containing a subquery?

    - by aidan
    I have two tables, House and Person. For any row in House, there can be 0, 1 or many corresponding rows in Person. But, of those people, a maximum of one will have a status of "ACTIVE", the others will all have a status of "CANCELLED". e.g. SELECT * FROM House LEFT JOIN Person ON House.ID = Person.HouseID House.ID | Person.ID | Person.Status 1 | 1 | CANCELLED 1 | 2 | CANCELLED 1 | 3 | ACTIVE 2 | 1 | ACTIVE 3 | NULL | NULL 4 | 4 | CANCELLED I want to filter out the cancelled rows, and get something like this: House.ID | Person.ID | Person.Status 1 | 3 | ACTIVE 2 | 1 | ACTIVE 3 | NULL | NULL 4 | NULL | NULL I've achieved this with the following sub select: SELECT * FROM House LEFT JOIN ( SELECT * FROM Person WHERE Person.Status != "CANCELLED" ) Person ON House.ID = Person.HouseID ...which works, but breaks all the indexes. Is there a better solution that doesn't? I'm using MySQL and all relevant columns are indexed. EXPLAIN lists nothing in possible_keys. Thanks.

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