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  • Easiest way to rename a model using Django/South?

    - by vaughnkoch
    Hi everyone, I've been hunting for an answer to this on South's site, google, and SO, but couldn't find a simple way to do this. I want to rename a Django model using South. Say you have the following: class Foo(models.Model): name = models.CharField() class FooTwo(models.Model): name = models.CharField() foo = models.ForeignKey(Foo) and you want to convert Foo to Bar, namely class Bar(models.Model): name = models.CharField() class FooTwo(models.Model): name = models.CharField() foo = models.ForeignKey(Bar) To keep it simple, I'm just trying to change the name from Foo to Bar, but ignore the 'foo' member in FooTwo for now. What's the easiest way to do this using South? a) I could probably do a data migration, but that seems pretty involved. b) Write a custom migration, e.g. db.rename_table('city_citystate', 'geo_citystate'), but I'm not sure how to fix the foreign key in this case. c) An easier way that you know? Thanks!

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  • The conceptual process of populating related tables in a database (MySql) from a CSV file

    - by user322772
    I'm new to relational databases and all the material I've read covered primary and foreign keys, normal forms, and joins but left out to populate the database once it's created. How do you import a CSV file so the fields match their related table? Say you were tying to build a beer database and had a CSV file with each line as a record. Header: brewer, beer_name, country, city, state, beer_category, beer_type, alcohol_content Record 1: Anheuser-Busch, Budweiser, United States, St. Louis, Mo, Pale lager, Regular, 5.0% Record 2: Anheuser-Busch, Bud Light, United States, St. Louis, Mo, Pale lager Light, 4.2% Record 3: Miller Brewing Company, Miller Lite, United States, Milwaukee, WI, Pale lager, Light, 4.2% You can create a "Brewer" table and a "Beer" table. When importing how does you connect the primary keys between the tables?

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  • What resources will help me understand the fundamentals of Relational Database Design.

    - by Rachel
    This are few of the fundamental database questions which has always given me trouble. I have tried using google and wiki but I somehow I miss out on understanding the functionality rather than terminology. If possible would really appreciate if someone can share more insights on this questions using some visual representative examples. What is a key? A candidate key? A primary key? An alternate key? A foreign key? What is an index and how does it help your database? What are the data types available and when to use which ones?

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  • SQL Query in NHibernate diction

    - by Jan-Frederik Carl
    I have a SQL Query which works in SQL Management Studio: Select Id From table t Where t.Date= (Select Max(Date) From ( Select * From table where ReferenceId = xy) u) Reason is, from all entries with a certain foreign key, I want to receive the one with the highest date. I tried to reform this Query for use in NHibernate, and I got IQuery query = session.CreateQuery(String.Format( @"Select t.Id From table t Where t.Date = (Select Max(Date) From (Select * From table t where t.ReferenceItem.Id = " + item.ReferenceItem.Id + ")u)")); I get the error message: "In expected" How do I have to form the NHibernate query? What does the "In" mean?

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  • DataMapper: using auto_migrate! with many-to-many dependencies?

    - by pschuegr
    Hi, I'm trying to migrate my app from MySql to Postgresql, using Rails3-pre and the latest DataMapper. I have several models which are related through many-to-many relationships using :through = Resource, which means that DataMapper creates a join table with foreign keys for both models. I can't auto_migrate! these changes, because I keep getting this: ERROR: cannot drop table users because other objects depend on it DETAIL: constraint artist_users_owner_fk on table artist_users depends on table users constraint site_users_owner_fk on table site_users depends on table users HINT: Use DROP ... CASCADE to drop the dependent objects too. I have tried everything I can think of, and thought I had things working when I added :constraint = :skip to the field definition, but I keep getting that error back when I try and run auto_migrate. I thought that :skip meant that it would ignore the dependents, but maybe that only applies for deleting rows and not dropping tables? I should mention that I can run auto_migrate after i nuke the db once, but after that, errors. Any suggestions or advice much appreciated.

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  • Left Join not returning all rows

    - by DisgruntledGoat
    I have this query in MySQL: SELECT pr.*, pr7.value AS `room_price_high` FROM `jos_hp_properties` pr LEFT OUTER JOIN `jos_hp_properties2` pr7 ON pr7.property=pr.id WHERE pr7.field=23 The jos_hp_properties table has 27 rows but the query only returns one. Based on this question I think it may be because of the WHERE clause. The jos_hp_properties2 table has fields id, property, field, value, where field is a foreign key to a third table (which I don't need to get data from). Is there a way to select all the rows from the first table, including the value from table #2 where the field is 23 (or NULL if there is no field 23)?

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  • ValueError: too many values to unpack in a tuple

    - by falosi
    Please put some light on why am getting a too many to unpack (ValueError in my for loop).Have tried deb naislist = [('CONTROL FILE', '0', '0', '0'), ('REDO LOG', '0', '0', '0'), ('ARCHIVED LOG', '.69', '.59', '3'), ('BACKUP PIECE', '46.54', '0', '192'), ('IMAGE COPY', '0', '0', '0'), ('FLASHBACK LOG', '10.15', '6.31', '82'), ('FOREIGN ARCHIVED LOG', '0', '0', '0')] print "size of naislist is ",len((naislist)) heading = ('MAIN MENU', 'LEVELS', 'LEVEL2', 'LEVEL3') rearrange = dict(zip((0, 1, 2, 3), (len(str(x)) for x in heading))) for tu, x in naislist: rearrange.update((i, max(rearrange[i], len(str(el)))) for i, el in enumerate(tu)) rearrange[4] = max(rearrange[4], len(str(x))) forkit = '|'. join('%%-%ss' % rearrange[i] for i in xrange(0, 4)) print '\n'.join((forkit % heading, '-|-'.join(rearrange[i] * '-' for i in xrange(4)), '\n'.join(forkit % (a, b, c, d) for (a, b, c), d in naislist)))

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  • Finding final/effective web.config values (from inherited configurations)

    - by gregmac
    Are there any apps that can show the final configuration as applied to a particular application directory? What I'm picturing is something along the lines of FireBug's CSS viewer. Basically, it should show the equivalent single web.config file (as if you only had one), with all the values that apply to the directory in question, with each element (or even attribute) annotated with its source (the real .config file it came from). This would greatly help deploying applications into foreign environments (eg, customer sites) where they sometimes have strange configs, that add in global includes (eg, they put the include in machine.config, instead of the web.config for that app) or have allowOverride=false, etc.

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  • Database Design Question

    - by deniz
    Hi, I am designing a database for a project. I have a table that has 10 columns, most of them are used whenever the table is accessed, and I need to add 3 more rows; View Count Thumbs Up (count) Thumbs Down (Count) which will be used on %90 of the queries when the table is accessed. So, my question is that whether it is better to break the table up and create new table which will have these 3 columns + Foreign ID, or just make it 13 columns and use no joins? Since these columns will be used frequently, I guess adding 3 more columns is better, but if I need to create 10 more columns which will be used %90 of the time, should I add them as well, or create a new table and use joins? I am not sure when to break the table if the columns are used very frequently. Do you have any suggestions? Thanks in advance,

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  • Approach for altering Primary Key from GUID to BigInt in SQL Server related tables

    - by Tom
    I have two tables with 10-20 million rows that have GUID primary keys and at leat 12 tables related via foreign key. The base tables have 10-20 indexes each. We are moving from GUID to BigInt primary keys. I'm wondering if anyone has any suggestions on an approach. Right now this is the approach I'm pondering: Drop all indexes and fkeys on all the tables involved. Add 'NewPrimaryKey' column to each table Make the key identity on the two base tables Script the data change "update table x, set NewPrimaryKey = y where OldPrimaryKey = z Rename the original primarykey to 'oldprimarykey' Rename the 'NewPrimaryKey' column 'PrimaryKey' Script back all the indexes and fkeys Does this seem like a good approach? Does anyone know of a tool or script that would help with this? TD: Edited per additional information. See this blog post that addresses an approach when the GUID is the Primary: http://www.sqlmag.com/blogs/sql-server-questions-answered/sql-server-questions-answered/tabid/1977/entryid/12749/Default.aspx

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  • Django - Passing arguments to models through ForeignKey attributes

    - by marshall
    I've got a class like this: class Image (models.Model): ... sizes = ((90,90), (300,250)) def resize_image(self): for size in sizes: ... and another class like this: class SomeClassWithAnImage (models.Model): ... an_image = models.ForeignKey(Image) what i'd like to do with that class is this: class SomeClassWithAnImage (models.Model): ... an_image = models.ForeignKey(Image, sizes=((90,90), (150, 120))) where i'm can specify the sizes that i want the Image class to use to resize itself as a argument rather than being hard coded on the class. I realise I could pass these in when calling resize_image if that was called directly but the idea is that the resize_image method is called automatically when the object is persisted to the db. if I try to pass arguments through the foreign key declaration like this i get an error straight away. is there an easy / better way to do this before I begin hacking down into django?

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  • How to delete refClass record in Doctrine?

    - by terrani
    Hi all! I have many-to-many relations with the following tables. post tag post_tag I created three classes with Doctrine, so I have the following classes as well. BasePost BaseTag BasePostTag in the setUp() method, I defined relations. I like to delete tag record when I delete post record. So I simply put cascade as descirbed on Doctrine document. $this->hasMany("Tag as Tags",array( 'refClass' => 'PostTag', 'local'=>'object_id', 'foreign'=>'tag_id', 'cascade'=> array('delete') )); it works without a problem. My questions is, how do I delete a record from post_tag table? Do I need to create a query myself?

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  • How to configure Hibernate database reverse engineering tool to map database table relation as a ent

    - by Piotr Kochanski
    Is it possible to configure Hibernate reverse engineering and code generation tool in such a way that one-to-many relation between tables is mapped to entities inheritance instead of enrites relation? I have Person table and Employee table, which are related with the foreign key (Person contains basic information, Employee the rest). In my Java code I would like this relation mapped to inheritance Employee extends Person. This can be done by hand, but maybe I missed some custom configuration parameter that I can use. I couldn't find any official documentation - docs link on RedHat Hibernate page (http://www.hibernate.org/5.html#A10) is broken...

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  • Check if row already exists, if so tell the referenced table the id

    - by flhe
    Let's assume I have a table magazine: CREATE TABLE magazine ( magazine_id integer NOT NULL DEFAULT nextval(('public.magazine_magazine_id_seq'::text)::regclass), longname character varying(1000), shortname character varying(200), issn character varying(9), CONSTRAINT pk_magazine PRIMARY KEY (magazine_id) ); And another table issue: CREATE TABLE issue ( issue_id integer NOT NULL DEFAULT nextval(('public.issue_issue_id_seq'::text)::regclass), number integer, year integer, volume integer, fk_magazine_id integer, CONSTRAINT pk_issue PRIMARY KEY (issue_id), CONSTRAINT fk_magazine_id FOREIGN KEY (fk_magazine_id) REFERENCES magazine (magazine_id) MATCH SIMPLE ON UPDATE NO ACTION ON DELETE NO ACTION ); Current INSERTS: INSERT INTO magazine (longname,shotname,issn) VALUES ('a long name','ee','1111-2222'); INSERT INTO issue (fk_magazine_id,number,year,volume) VALUES (currval('magazine_magazine_id_seq'),'8','1982','6'); Now a row should only be inserted into 'magazine', if it does not already exist. However if it exists, the table 'issue' needs to get the 'magazine_id' of the row that already exists in order to establish the reference. How can i do this? Thx in advance!

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  • Entity Framework: Setting EntityReference EntityKey causes exception on save

    - by NYSystemsAnalyst
    I have a table with a ModifiedUserID field that is a foreign key to a User table. In entity framework, I'm loading the first table, but not the users table. I have the user ID of the current user, and would like to set the ModifiedUserID to that value for all entities that have been modified prior to saving. Before calling SaveChanges(), I use the ObjectStateManager to get all modified entities. Since I do not have the user object, but I do have the user ID, I set the EntityReference.EntityKey property as follows: entity.UserReference.EntityKey = New EntityKey("MyContainer.User", "UserID", DatabaseUserID) This works fine, but when I execute SaveChanges(), I receive the following error: A relationship is being added or deleted from an AssociationSet 'FK_Table1_User'. With cardinality constraints, a corresponding 'Table1' must also be added or deleted. Now, I see that setting the EntityReference.EntityKey creates a new AssociationSet entry, but how to I prevent this error?

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  • InnoDB not supported by webhost. What now?

    - by Peter Perhác
    I was developing a small WAMP web application on my laptop, where I have an instance of mySQL running and I chose InnoDB for my DB engine. After several weeks' development I wanted to make it available to the public and found out the database server provided by my web host does not support InnoDB, only MyISAM. The create-and-populate script generated from the innoDB schema on my laptop, when executed against the live database, can manage to create individual TABLES but then runs into problems creating the VIEWs. Are views not supported in MyISAM? I know FOREIGN KEYs are not. That's very much why I made the choice of InnoDB... What are my chances of making my innoDB schema design work with myISAM? Is there any straightforward way of converting the whole schema from one storage engine to the other? Should I look for another web host that does provide a mysql db that supports innoDB?

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  • SQL? "Show me all the Activities that can be performed by User X."

    - by Casey Fulton
    I'm at my wits end. I've searched like crazy, read plenty of database textbooks and God knows how many online guides, blogs and forums. Can someone put me out of my misery? PseudoSchema Diagram (Warning: although pretty, not in a format even remotely approaching ER diagrams! Primary keys are bold, foreign keys are italics.) Given the above set of tables relating Users to Groups to Privileges, and then a set of Activities that can each require a Privilege to perform, how do you find out this: Show me all the Activities that can be performed by User X. That is: User X is a member of groups G and F; groups G and F correlate to privileges P, Q, R and S; show me all the activities that require privileges either P, Q, R or S. How do you do this?

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  • Database Design for One to One relationships

    - by Greelmo
    I'm trying to finalize my design of the data model for my project, and am having difficulty figuring out which way to go with it. I have a table of users, and an undetermined number of attributes that apply to that user. The attributes are in almost every case optional, so null values are allowed. Each of these attributes are one to one for the user. Should I put them on the same table, and keep adding columns when attributes are added (making the user table quite wide), or should I put each attribute on a separate table with a foreign key to the user table. I have decided against using the EAV model. Thanks!

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  • Saving related model objects

    - by iHeartDucks
    I have two related models (one to many) in my django app and When I do something like this ObjBlog = Blog() objBlog.name = 'test blog' objEntry1 = Entry() objEntry1.title = 'Entry one' objEntry2 = Entry() objEntry2.title = 'Entry Two' objBlog.entry_set.add(objEntry1) objBlog.entry_set.add(objEntry2) I get an error which says "null value in column and it violates the foreign key not null constraint". None of my model objects have been saved. Do I have to save the "objBlog" before I could set the entries? I was hoping I could call the save method on objBlog to save it all. NOTE: I am not creating a blog engine and this is just an example.

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  • MySQL query for initial filling of order column

    - by Sejanus
    Sorry for vague question title. I've got a table containing huge list of, say, products, belonging to different categories. There's a foreign key column indicating which category that particular product belongs to. I.e. in "bananas" row category might be 3 which indicates "fruits". Now I added additional column "order" which is for display order within that particular category. I need to do initial ordering. Since the list is big, I dont wanna change every row by hand. Is it possible to do with one or two queries? I dont care what initial order is as long as it starts with 1 and goes up. I cant do something like SET order = id because id counts from 1 up regardless of product category and order must start anew from 1 up for every different category.

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  • How to search in this activerecord example?

    - by Horace Ho
    Two models: Invoice :invoice_num string :date datetime . . :disclaimer_num integer (foreign key) Disclaimer :disclaimer_num integer :version integer :body text For each disclaimer there are multiple versions and will be kept in database. This is how I write the search (simplified): scope = Invoice.scoped({ :joins => [:disclaimer] }) scope = scope.scoped :conditions => ["Invoice.invoice_num = ?", "#{params[:num]}"] scope = scope.scoped :conditions => ["Disclaimer.body LIKE ?", "%#{params[:text]}%"] However, the above search will search again all versions of the disclaimer. How can I limit the search to only the last disclaimer (i.e. the version integer is the maximum). Please note: Invoice does not keep the version number. New disclaimers will be added to disclaimer table and keep old versions.

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  • Fulltext for innoDB? or a good solution for php app

    - by Joshua
    I have a table I want to run a fulltext search on, but it is currently innoDB and is using a lot of foreign keys for other kinds of queries. Should I make like a 1:1 "meta-data" table that is myisam for fulltext? Also I am reading some things that say that fulltext corrupts MySQL tables pretty randomly? I dunno, the articles are a couple years old, maybe they've fixed that in 5+? If not what's a good solution for searching? Zend_Lucene seems cool but slow, even with caching, for the client's large tables and autocomplete functionality et al.

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  • JSF skips phases - How to debug that?

    - by Pentius
    Hey fellows, I have to debug a foreign jsf application thanks god. The problem is, that I submit a form, but the values aren't carried over. With a phase listener I can see, that the life cycle doesn't run completely through, so to say it skips phase 2 -5: After the restore view phase, the render response phase is directly called. I miss the apply values, validation, update model actions and so on. So, this could be a chicken-and-egg problem: 1. The responsible phases aren't called, so the new form input can't be carried over. 2. The system doesn't recognize any new input and therefore directly renders after restoring the view. I checked that there is no call of responseComplete() oder renderResponse(). I'm stuck somehow. Any idea to validate one of the two hypothesis? Or how to debug that in general? Did anybody have a similar problem?

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  • how to model a many to many relationship

    - by Maulin
    Here is the scenario, Articles have many Comments Users can write many Comments for many Articles The comments table contains both user_id article_id as foreign keys My models are set up like so class User < ActiveRecord::Base has_many :comments has_many :articles, :through => :comments class Article < ActiveRecord::Base has_many :comments has_many :users, :through => :comments class Comment < ActiveRecord::Base belongs_to :users belongs_to :articles My routes.rb has the following code map.resources :articles, :has_many => :comments map.resources :users, :has_many => :comments which produces the following routes new_article_comment edit_article_comment new_user_comment edit_user_comment etc... This is not what I want (atleast not what I think I want), since comments must always be related to users and article, how can I get a route like so new_user_article_comment edit_user_article_comment Then I could just do new_user_article_comment_path([@user, @article]) to create a new comment

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  • Exploring search options for PHP

    - by Joshua
    I have innoDB table using numerous foreign keys, but we just want to look up some basic info out of it. I've done some research but still lost. 1) How can I tell if my host has Sphinx installed already? I don't see it as an option for table storage method (i.e. innodb, myisam). 2) Zend_Search_Lucene, responsive enough for AJAX functionality of millions of records? 3) Mirror my innoDB with a myisam? Make every innodb transaction end with a write to the myisam, then use 1:1 lookups? How would I do this automagically? This should make MyISAM ACID-compliant and free(er) from corruption no? 4) PostgreSQL fulltext queries don't even look like SQL to me wtf, I don't have time to learn a new SQL syntax I need noob options 5) ???????????????????? This is high volume site on a decently-equipped VPS Thanks very much for any ideas.

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