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  • Entity Framework naming conventions for many-to-many link tables

    - by TimothyP
    Hi, We are designing a SQL Server database with link tables for many-to-many relations. The question is are there any best practices for naming these kinds of tables for use with the entity framework? Let's say there's a table Customer and Address Then there is a link table between them, what do we call it? CustomerAddress ? Or something else? Thnx

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  • High-quality ERD generator for PostgresQL under Linux?

    - by Dave Jarvis
    Background MySQL Workbench can produce appealing and high-quality ERDs such as: Research I have not found a tool that even comes close for PostgreSQL. Tools I have found: dbVisualizer - Yellow squares. AquaFold - Yellow squares. SQL Developer - Coloured squares. Dia - Coloured squares. SchemaBank - Can't export to PNG; looks okay, nothing stellar. SchemaSpy - XML export makes it possible to write an XSL skin... Gliffy - Incompatible Flash version. Druid - No. pgAdmin3 - Not applicable? phpPgAdmin - Couldn't login without a 30-minute configuration battle. Requirements Looking for an ERD tool: Visually stunning by default Can reverse-engineer a PostgreSQL (or JDBC-compliant) database Runs on Linux (or under WINE) Export high-resolution PNG (or SVG) FOSS

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  • doctrine findby relation

    - by iggnition
    I'm having trouble selecting a subset of data with doctrine. I have 3 tables Location Contact Contact_location The contact and location tables hold a name and an id the other table holds only ID's. For instance: Location loc_id: 1 name: detroit Contact contact_id: 1 name: Mike Contact_location loc_id: 1 contact_id: 1 In doctrine there is a many to many relation between the location and contact tables with contact_location as the ref_class. What i want to do is on my location page i want to find all contacts where for instance the loc_id = 1. I tried: $this->installedbases = Doctrine::getTable('contact')->findByloc_id(1); hoping doctrine would see the relation and get it, but it does not. How can i make doctrine search in relevant related tables? I read it can be done using Findby but i find the documentation unclear.

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  • NHibernate Legacy Database Mappings Impossible?

    - by Corey Coogan
    I'm hoping someone can help me with mapping a legacy database. The problem I'm describing here has plagued others, yet I was unable to find a real good solution around the web. DISCLAIMER: this is a legacy DB. I have no control over the composite keys. They suck and can't be changed no matter much you tell me they suck. I have 2 tables, both with composite keys. One of the keys from one table is used as part of the key to get a collection from the other table. In short, the keys don't fully match between the table. ClassB is used everywhere I would like to avoid adding properties for the sake of this mapping if possible. public class ClassA { //[PK] public string SsoUid; //[PK] public string PolicyNumber; public IList<ClassB> Others; //more properties.... } public class ClassB { //[PK] public string PolicyNumber; //[PK] public string PolicyDateTime; //more properties } I want to get an instance of ClassA and get all ClassB rows that match PolicyNumber. I am trying to get something going with a one-to-many, but I realize that this may technically be a many-to-many that I am just treating as one-to-many. I've tried using an association class but didn't get far enough to see if it works. I'm new to these more complex mappings and am looking for advice. I'm open to pretty much any ideas. Thanks, Corey

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  • Internal and External Bug-Tracking Setup

    - by devdude
    Most of you certainly use some kind of bugtracker. Maybe internally only, once a customer files a bug via email or phone you add a new ticket by yourself. Sometimes weekly project meetings can be great source of new tickets coming preferably in flavors of excel sheets that the PM on the other side of the table loves to maintain and chase after you. The more advanced (and transparent) version: Allow the customer to file (and see the progress of) his bugs directly into you bugtracker. Systems like JIRA allow you to use profiles to have certain access rights, etc. But now the question: The bug raised by a user not necessary translates into 1 bug in a specific module/method/EJB/class. The version of the (your) web application he uses does not translate into the version of the class that is causing the error. How you maintain the internal part of the ticket with all the nasty techy details and the same time the make-the-user-feel-good ticket (need more info, accepted, in progress,..) ? Creating 2 tickets for internal and external ? Link them ? Any smart recipes to share ?

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  • Easy way to observe user activity - how improve my database structure.

    - by Thomas
    Welcome, I need some advise to improve perfomence my web application. In the begin I had this structure of database: USER -id (Primary Key) -name -password -email .... PROFILE -user Primary Key, Foreign Key (USER) -birthday -region -photoFile ... PAGES -id (Primary Key) -user Foreign Key(USER) -page -date COMMENTS -id (Primary Key) -user Foreign Key(USER) -page Foreign Key(PAGE) -comment -date FAVOURITES_PAGES -id (Primary Key) -user Foreign Key(USER) -favourite_page Foreign Key(PAGE) -date but now one of the most important page of website is observatory, when everyone can observe activity others users. So I need select all pages, comments and favourites pages some users and display it in one list, sorted by date. For better perfomance (I think) I changed my structure to this: table USER and PROFILE without changes ACTIVITY (additional table- have common fields: user,date) -id (Primary Key) -user Foreign Key(USER) -date -page Foreign Key(PAGE) -comment Foreign Key(COMMENTS) -favourite_page Foreign Key(FAVOURITES_PAGES) PAGES -id (Primary Key) -page COMMENTS -id (Primary Key) -page Foreign Key(PAGE) -comment FAVOURITES_PAGES -id (Primary Key) -favourite_page Foreign Key(PAGE) So now it is very easy get sorted records from all tables. But I have no only foreign key to PAGES, COMMENTS and FAVOURITES_PAGES in ACTIVITY table - there is about ten Foreign Key fields and in one record only one have value, others have None: ACTIVITY id user date page comment ... 1 2 2010-02-23 None 1 2 1 2010-02-21 1 None .... It is corect solution. When I display about 40 records in one page (pagination) I must wait about one secound, but database is almost emty (a few users and about 100 records in others tables). It is depends on amount records per page - I have checked it, but why it takes too long time, becouse of relationships? The website is built in Python/Django. Any advices/opinion?

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  • Rails Foreign key setup question.

    - by James P. Wright
    I'm just (re)starting playing around with Rails and I'm making a little card game app. I cannot seem to figure out my Foreign Key setups. Say I have 4 objects: - Game - Player - Hand - Card A Game has many Players, which have many Hands which have many Cards. But the cards are also independent of a Hand, Player and Game. For example, I have 6 Cards in my database (1 to 6). It is possible that Card 3 could be in 2 Players Hands in the same Game. How can I set up my keys for this? Should I just create another object for "CardInHand" to simplify it?

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  • How to do fixed price quote for design sessions?

    - by Shaul
    Normally when I do a system for a customer, I do design sessions on an hourly rate and then come out with a fixed price quotation for the full system development. Now this customer has thrown me a curveball: he doesn't want an hourly rate for design, either - he wants me to quote a fixed price to do all the design, too! Not that he's trying to cheap out, but he doesn't want to be in a situation where the longer design stretches out, the more he has to pay - and I can understand that. For the business layer it was actually not too difficult to work with this, because from his original functional spec I got a good idea of what the core business objects were, and in our design agreement I defined several objects which would be covered by a fixed design price; if any new non-trivial objects were discovered, they would be considered variances, and those would be billed on an hourly rate. So far so good. But when it comes to the UI, things start getting a lot more woolly. How many screens will there be? Don't know yet. What's going to be on each screen? Don't know yet. All we know is that it's a "dashboard" type of system, and there will be a lot of visual reporting involved e.g. gauges, graphs, etc. So maybe make it fixed price per screen design? Not a great definition; he might say that everything is going to be on one screen. Maybe a price per "visual report" design, including ability to slice & dice? Again not so easy - it might be that the entire system is just one report, and all the intelligence is going to go into how to present that segmentation. Anyone have any ideas how to do a fixed price quotation for a UI design like this?

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  • Model relationships in ASP.NET MVC

    - by Fabiano
    Hi I recently started evaluating ASP.NET MVC. While it is really easy and quick to create Controllers and Views for Models with only primitive properties (like shown in the starter videos from the official page) I didn't find any good way to work with references to complex types. Let's say, I have these Models: public class Customer { public int Id { get; set; } public string Name { get; set; } public Address Address { get; set; } public IList<Order> Orders { get; set; } } public class Address { public int Id { get; set; } public string ..... ..... } public class Order { public int Id { get; set; } public Customer Customer { get; set; } public string OrderName { get; set; } ..... } Note that I don't have foreign keys in the models (like it's typical for LINQ to SQL, which is also used in the sample video) but an object reference. How can I handle such references in asp.net mvc? Does someone has some good tips or links to tutorials about this problem? maybe including autobinding with complex types.

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  • Doctrine does not export relation properly

    - by iggnition
    Hi, I've got a MySQL 5.1.41 database which i'm trying to fill with doctrine, but doctrine does not insert the relations correctly. My YAML is: Locatie: connection: doctrine tableName: locatie columns: loc_id: type: integer(4) fixed: false unsigned: false primary: true autoincrement: true org_id: type: integer(4) fixed: false unsigned: false primary: false notnull: false autoincrement: false naam: type: string(30) fixed: false unsigned: false primary: false notnull: true autoincrement: false straat: type: string(30) fixed: false unsigned: false primary: false notnull: true autoincrement: false huisnummer: type: integer(4) fixed: false unsigned: false primary: false notnull: true autoincrement: false huisnummer_achtervoegsel: type: string(3) fixed: false unsigned: false primary: false notnull: false autoincrement: false plaats: type: string(25) fixed: false unsigned: false primary: false notnull: true autoincrement: false postcode: type: string(6) fixed: false unsigned: false primary: false notnull: true autoincrement: false telefoon: type: string(12) fixed: false unsigned: false primary: false notnull: true autoincrement: false opmerking: type: string() fixed: false unsigned: false primary: false notnull: false autoincrement: false inloggegevens: type: string() fixed: false unsigned: false primary: false notnull: false autoincrement: false relations: Organisatie: local: org_id foreign: org_id type: one onDelete: CASCADE onUpdate: CASCADE Organisatie: connection: doctrine tableName: organisatie columns: org_id: type: integer(4) fixed: false unsigned: false primary: true autoincrement: true naam: type: string(30) fixed: false unsigned: false primary: false notnull: true autoincrement: false straat: type: string(30) fixed: false unsigned: false primary: false notnull: true autoincrement: false huisnummer: type: integer(4) fixed: false unsigned: false primary: false notnull: true autoincrement: false huisnummer_achtervoegsel: type: string(3) fixed: false unsigned: false primary: false notnull: false autoincrement: false plaats: type: string(25) fixed: false unsigned: false primary: false notnull: true autoincrement: false postcode: type: string(6) fixed: false unsigned: false primary: false notnull: true autoincrement: false telefoon: type: string(12) fixed: false unsigned: false primary: false notnull: true autoincrement: false opmerking: type: string(255) fixed: false unsigned: false primary: false notnull: false autoincrement: false relations: Locatie: local: org_id foreign: org_id type: many Now if a make an organisation and then create a location which has a foreignkey to organisation everything is fine. but when i try to update the org_id with phpmyadmin i get a contraint error. If i manually set the foreign key to ON_UPDATE CASCADE it does work. Why does doctrine not set this option? I got it to work in Propel, but i really want to use doctrine for this.

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  • Add note model in Rails

    - by dannymcc
    Hi Everyone, I am following the 15 minute blog tutorial on Ruby on Rails .com: http://media.rubyonrails.org/video/rails_blog_2.mov and am stumbling into some issues. I am using the following alterations to the names in the tutorial: posts = kases comments = notes I have setup the models as follows: class Kase < ActiveRecord::Base validates_presence_of :jobno has_many :notes belongs_to :company # foreign key: company_id belongs_to :person # foreign key in join table belongs_to :surveyor, :class_name => "Company", :foreign_key => "appointedsurveyor_id" belongs_to :surveyorperson, :class_name => "Person", :foreign_key => "surveyorperson_id" def to_param jobno end and... class Note < ActiveRecord::Base belongs_to :kase end The Notes controller look like this: # POST /notes # POST /notes.xml def create @kase = Kase.find(params[:kase_id]) @note = @kase.notes.build(params[:note]) redirect_to @kase end and the database scheme for Kases looks like this: create_table "notes", :force => true do |t| t.integer "kase_id" t.text "body" t.datetime "created_at" t.datetime "updated_at" end and for kases... create_table "kases", :force => true do |t| t.string "jobno" t.date "dateinstructed" t.string "clientref" t.string "clientcompanyname" t.text "clientcompanyaddress" t.string "clientcompanyfax" t.string "casehandlername" t.string "casehandlertel" t.string "casehandleremail" t.text "casesubject" t.string "transport" t.string "goods" t.string "claimantname" t.string "claimantaddressline1" t.string "claimantaddressline2" t.string "claimantaddressline3" t.string "claimantaddresscity" t.string "claimantaddresspostcode" t.string "claimantcontact" t.string "claimanttel" t.string "claimantmob" t.string "claimantemail" t.string "claimanturl" t.string "lyingatlocationname" t.string "lyingatlocationaddressline1" t.string "lyingatlocationaddressline2" t.string "lyingatlocationaddressline3" t.string "lyingatlocationaddresscity" t.string "lyingatlocationaddresspostcode" t.string "lyingatlocationcontactname" t.string "lyingattel" t.string "lyingatmobile" t.string "lyingatlocationurl" t.text "comments" t.string "invoicenumber" t.string "netamount" t.string "vat" t.string "grossamount" t.date "dateclosed" t.date "datepaid" t.datetime "filecreated" t.string "avatar_file_name" t.string "avatar_content_type" t.integer "avatar_file_size" t.datetime "avatar_updated_at" t.datetime "created_at" t.datetime "updated_at" t.string "kase_status" t.string "invoice_date" t.integer "surveyorperson_id" t.integer "appointedsurveyor_id" t.integer "person_id" t.string "company_id" t.string "dischargeamount" t.string "dishchargeheader" t.text "highrisesubject" end Whenever I enter a note into the kase show view's note entry form: <h2>Notes</h2> <div id="sub-notes"> <%= render :partial => @kase.notes %> </div> <% form_for [@kase, Note.new] do |f| %> <p> <%= f.label :body, "New Note" %><br /> <%= f.text_area :body %> </p> <p><%= f.submit "Add Note" %></p> <% end %> partial: <% div_for note do %> <p> <strong>Created <%= time_ago_in_words(note.created_at) %> ago</strong><br /> <%= h(note.body) %> </p> <% end %> I get the following error: ActiveRecord::RecordNotFound in NotesController#create Couldn't find Kase with ID=Test Case I have tried removing the def to_param jobno end from the kase model, but the same error shows. Any ideas what I'm missing? Thanks, Danny

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  • Django foreign keys cascade deleting and "related_name" parameter (bug?)

    - by Wiseman
    In this topic I found a good way to prevent cascade deleting of relating objects, when it's not neccessary. class Factures(models.Model): idFacture = models.IntegerField(primary_key=True) idLettrage = models.ForeignKey('Lettrage', db_column='idLettrage', null=True, blank=True) class Paiements(models.Model): idPaiement = models.IntegerField(primary_key=True) idLettrage = models.ForeignKey('Lettrage', db_column='idLettrage', null=True, blank=True) class Lettrage(models.Model): idLettrage = models.IntegerField(primary_key=True) def delete(self): """Dettaches factures and paiements from current lettre before deleting""" self.factures_set.clear() self.paiements_set.clear() super(Lettrage, self).delete() But this method seems to fail when we are using ForeignKey field with "related_name" parameter. As it seems to me, "clear()" method works fine and saves the instance of "deassociated" object. But then, while deleting, django uses another memorized copy of this very object and since it's still associated with object we are trying to delete - whooooosh! ...bye-bye to relatives :) Database was arcitectured before me, and in somewhat odd way, so I can't escape these "related_names" in reasonable amount of time. Anybody heard about workaround for such a trouble?

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  • get_or_create generic relations in Django & python debugging in general

    - by rabidpebble
    I ran the code to create the generically related objects from this demo: http://www.djangoproject.com/documentation/models/generic_relations/ Everything is good intially: >>> bacon.tags.create(tag="fatty") <TaggedItem: fatty> >>> tag, newtag = bacon.tags.get_or_create(tag="fatty") >>> tag <TaggedItem: fatty> >>> newtag False But then the use case that I'm interested in for my app: >>> tag, newtag = bacon.tags.get_or_create(tag="wholesome") Traceback (most recent call last): File "<console>", line 1, in <module> File "/usr/local/lib/python2.6/dist-packages/django/db/models/manager.py", line 123, in get_or_create return self.get_query_set().get_or_create(**kwargs) File "/usr/local/lib/python2.6/dist-packages/django/db/models/query.py", line 343, in get_or_create raise e IntegrityError: app_taggeditem.content_type_id may not be NULL I tried a bunch of random things after looking at other code: >>> tag, newtag = bacon.tags.get_or_create(tag="wholesome", content_type=TaggedItem) ValueError: Cannot assign "<class 'generics.app.models.TaggedItem'>": "TaggedItem.content_type" must be a "ContentType" instance. or: >>> tag, newtag = bacon.tags.get_or_create(tag="wholesome", content_type=TaggedItem.content_type) InterfaceError: Error binding parameter 3 - probably unsupported type. etc. I'm sure somebody can give me the correct syntax, but the real problem here is that I have no idea what is going on. I have developed in strongly typed languages for over ten years (x86 assembly, C++ and C#) but am new to Python. I find it really difficult to follow what is going on in Python when things like this break. In the languages I mentioned previously it's fairly straightforward to figure things like this out -- check the method signature and check your parameters. Looking at the Django documentation for half an hour left me just as lost. Looking at the source for get_or_create(self, **kwargs) didn't help either since there is no method signature and the code appears very generic. A next step would be to debug the method and try to figure out what is happening, but this seems a bit extreme... I seem to be missing some fundamental operating principle here... what is it? How do I resolve issues like this on my own in the future?

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  • sql foreign keys

    - by Paul Est
    I was create tables with the syntax in phpmyadmin: DROP TABLE IF EXISTS users; DROP TABLE IF EXISTS info; CREATE TABLE users ( user_id int unsigned NOT NULL auto_increment, email varchar(100) NOT NULL default '', pwd varchar(32) NOT NULL default '', isAdmin int(1) unsigned NOT NULL, PRIMARY KEY (user_id) ) TYPE=INNODB; CREATE TABLE info ( info_id int unsigned NOT NULL auto_increment, first_name varchar(100) NOT NULL default '', last_name varchar(100) NOT NULL default '', address varchar(300) NOT NULL default '', zipcode varchar(100) NOT NULL default '', personal_phone varchar(100) NOT NULL default '', mobilephone varchar(100) NOT NULL default '', faxe varchar(100) NOT NULL default '', email2 varchar(100) NOT NULL default '', country varchar(100) NOT NULL default '', sex varchar(1) NOT NULL default '', birth varchar(1) NOT NULL default '', email varchar(100) NOT NULL default '', PRIMARY KEY (info_id), FOREIGN KEY (email) REFERENCES users(email) ON UPDATE CASCADE ON DELETE CASCADE ) TYPE=INNODB; But shows the error "#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'TYPE=INNODB' at line 11 " If i remove the TYPE=INNODB in the end of create the tables, it will show the error "#1005 - Can't create table 'curriculo.info' (errno: 150) ".

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  • Is there a declarative language for data definitions?

    - by Jekke
    Reading about WPF and thinking about my application's data store at the same time led me to wonder if there are any languages or tools that allow you to define relational data in a declarative way? A shallow Google search suggests no such thing exists. Yet it seems so obviously useful. The kind of tool I have in mind would declaratively describe (at least) entities, relationships and views is a platform-agnostic way that would act as an abstraction layer between data-driven applications and their datastores. Does any such tool exist?

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  • Django: many-to-one fields and data integrity

    - by John
    Let's say that I have a Person who runs an inventory system. Each Person has some Cars, and each Car has a very large number of Parts (thousands, let's say). A Person, Bob, uses a Django form to create a Car. Now, Bob goes to create some Parts. It is only at the form level that Django knows that the Parts belong to some specific Car, and that the Parts.ForeignKey(Car) field should only have a specific Car as a choice. When creating a Part, you have to mess with the form's constructor or similar in order to limit the choice of Cars to only the cars owned by Bob. It does not seem proper that to enforce this ownership at the form level. It seems that other users' Cars must be inaccessible to anyone but the owner of the Car. What do you all think about this, and is there any way to enforce this?

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  • Database relationships using phpmyAdmin (composite keys)

    - by Cool Hand Luke UK
    Hi, I hope this question is not me being dense. I am using phpmyAdmin to create a database. I have the following four tables. Don't worry about that fact place and price are optional they just are. Person (Mandatory) Item (Mandatory) Place (Optional) Price (Optional) Item is the main table. It will always have person linked. * I know you do joins in mysql for the tables. If I want to link the tables together I could use composite keys (using the ids from each table), however is this the most correct way to link the tables? It also means item will have 5 ids including its own. This all cause null values (apparently a big no no, which I can understand) because if place and price are optional and are not used on one entry to the items table I will have a null value there. Please help! Thanks in advance. I hope this makes sense.

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  • does the order a composite key is defined matter?

    I have a table with (col1,col2) as a composite primary key. create table twokeytable(col1 int,col2 int,constraint twokeytable_pk primary key (col1,col2)); and another table with col3,col4 collumns witha composite foreign key(col3,col4) which references the(col1,col2) primary key. For some processing I need to drop the foreign key and primary constraints .While restoring the constraints does order of the keys matter?. are these same? create table fktwokeytable(col3 int,col4 int,constraint fkaddfaa_fk foreign key(col4,col3) references twokeytable(col1,col2)) and create table fktwokeytable(col3 int,col4 int,constraint fkaddfaa_fk foreign key(col3,col4) references twokeytable(col1,col2))

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  • [rails] do we need database level constraints

    - by shrimpy
    i have the same problem as in the following post http://stackoverflow.com/questions/1451570/ruby-on-rails-database-migration-not-creating-foreign-keys-in-mysql-tables so i am wondering, why rails do not support generate foreign key by default??? it is not necessary??? or we suppose to do it manually?

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  • Problems getting foreign keys working in MySQL

    - by thehuby
    I've been trying to get a delete to cascade and it just doesn't seem to work. I'm sure I am missing something obvious, can anyone help me find it? I would expect a delete on the 'articles' table to trigger a delete on the corresponding rows in the 'article_section_lt' table. CREATE TABLE articles ( id INTEGER UNSIGNED PRIMARY KEY AUTO_INCREMENT, url_stub VARCHAR(255) NOT NULL UNIQUE, h1 VARCHAR(60) NOT NULL UNIQUE, title VARCHAR(60) NOT NULL, description VARCHAR(150) NOT NULL, summary VARCHAR(150) NOT NULL DEFAULT "", html_content TEXT, date DATE NOT NULL, updated TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP )ENGINE=INNODB; CREATE TABLE article_sections ( /* blog, news etc */ id INTEGER UNSIGNED PRIMARY KEY AUTO_INCREMENT, url_stub VARCHAR(255) NOT NULL UNIQUE, h1 VARCHAR(60) NOT NULL, title VARCHAR(60) NOT NULL, description VARCHAR(150) NOT NULL, summary VARCHAR(150) NOT NULL DEFAULT "", html_content TEXT NOT NULL DEFAULT "" )ENGINE=INNODB; CREATE TABLE article_section_lt ( fk_article_id INTEGER UNSIGNED NOT NULL REFERENCES articles(id) ON DELETE CASCADE, fk_article_section_id INTEGER UNSIGNED NOT NULL )ENGINE=INNODB;

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  • Type casting in TPC inheritance

    - by Mohsen Esmailpour
    I have several products like HotelProduct, FlightProduct ... which derived from BaseProduct class. The table of these products will be generated in TPC manner in database. There is OrderLine class which has a BaseProduct. My problem is when i select an OrderLine with related product i don't know how cast BaseProduct to derived product. for example i have this query: var order = (from odr in _context.Orders join orderLine in _context.OrderLines on odr.Id equals orderLine.OrderId join hotel in _context.Products.OfType<HotelProduct>() on orderLine.ProductId equals hotel.Id where odr.UserId == userId && odr.Id == orderId orderby odr.OrderDate descending select odr).SingleOrDefault(); In OrderLine i have BaseProduct properties not properties of HotelProduct. Is there any way to cast BaseProduct to derived class in OrderLine or any other solutions ?

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  • SQL - Two foreign keys that have a dependency between them

    - by Brian
    The current structure is as follows: Table RowType: RowTypeID Table RowSubType: RowSubTypeID FK_RowTypeID Table ColumnDef: FK_RowTypeID FK_RowSubTypeID (nullable) In short, I'm mapping column definitions to rows. In some cases, those rows have subtype(s), which will have column definitions specific to them. Alternatively, I could hang those column definitions that are specific to subtypes off their own table, or I could combine the data in RowType and RowSubType into one table and work with a single ID, but I'm not sure either is a better solution (if anything, I'd lean towards the latter, as we mostly end up pulling ColumnDefs for a given RowType/RowSubType). Is the current design SQL Blasphemy? If I keep the current structuree, how do I maintain that if RowSubTypeID is specified in ColumnDef, that it must correspond to the RowType specified by RowTypeID? Should I try to enforce this with a trigger or am I missing a simple redesign that would solve the problem?

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  • I want define tables from a part of my ER Diagram.

    - by M R Jafari
    I have a ER-Diagram (Show in http://www.4freeimagehost.com/show.php?i=f82997ca4d5d.png). In the diagram you see 2 entities and a 1:N relataion together. Project has 2 columns as ProjectID, ProjectName. Employee has 3 colums as EmployeeID, EmployeeName and ProjectID. A project has ONLY 1 project-manager and project-manager is a employee. What columns add them?

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