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  • how to design this relation in a DB schema

    - by raticulin
    I have a table Car in my db, one of the columns is purchaseDate. I want to be able to tag every car with a number of Policies (limited to 10 policies). Each policy has a time to life (ttl, a duration of time, like '5 years', '10 months' etc), that is, for how long since the car's purchaseDate the policy can be applied. I need to perform the following actions: when inserting a Car, it will be set with a number of Policies (at least one is set) sometimes a Car will be updated to add/remove a Policy searches must be done taking into account date/policies, for example: 'select all cars that are not covered by any policy as of today' My current design is (pol0..pol9 are the policies): CREATE TABLE Car ( id int NOT NULL IDENTITY(1,1), purchaseDate datetime NOT NULL, //more stuff... pol0 smallint default NULL, pol1 smallint default NULL, pol2 smallint default NULL, pol3 smallint default NULL, pol4 smallint default NULL, pol5 smallint default NULL, pol6 smallint default NULL, pol7 smallint default NULL, pol8 smallint default NULL, pol9 smallint default NULL, PRIMARY KEY (id) ) CREATE TABLE Policy ( id smallint NOT NULL, name varchar(50) collate Latin1_General_BIN NOT NULL, ttl varchar(100) collate Latin1_General_BIN NOT NULL, PRIMARY KEY (id) ) The problem I am facing is that the sql to perform the query above is a nightmare to write. As I don't know in which column each policy can be, so I have to check all columns for every policy etc etc. So I am wondering wether it is worth changing this. My questions are: The smallint as Policy id was chosen instead of an 'int IDENTITY' in order to save some space as there are going to be millions of Car records. It just adds complexity when creating a Policy as we must handle the id etc. Was it worth doing this? I am thinking that maybe there is a much better design? Obviously we could move the policy/car relation to its own table CarPolicy, benefits would be: no limit on 10 policies per car adding/removing etc much easier when only the default policy is applied (when no others are applied one called Default policy is applied), we could signal that by not having any entry in CarPolicy, now this is just done inserting the Default policy id in one of the columns. The cons are that we would need to change the DB, ORM classes etc. What would you recommend? Maybe there is another smart way to implement this that we are not aware without using the CarPolicy table?

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  • migrate database from sybase to mysql

    - by jindalsyogesh
    I have been trying to migrate a database from sybase to Mysql. This is my approach: Generate pojo classes from my sybase database using hibernate in eclipse Use these pojo classes to generate the schema in mysql database Then somehow migrate the data from sybase to mysql I guess this approach should work??? Please let me know if there is any better or easier approach. The thing is I am not even able to get the first step done. I added hibernate plugin in eclipse from this link: [http://download.jboss.org/jbosstools/updates/stable/][1] I added sybase jar file to my project classpath Then I added hibernate console configuration file Then I added hibernate configuration file Then I added hibernate code generation configuration When I try to run the code generation configuration file, I am getting java.lang.NullPointerException and I have no idea how to fix it. I searched a lot of forums, tried to google it, but I not able to find any solution. Can anybody tell me what mistake I am making here or point to some hibernate tutorial for eclipse??

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  • Scalable Database Tagging Schema

    - by Longpoke
    EDIT: To people building tagging systems. Don't read this. It is not what you are looking for. I asked this when I wasn't aware that RDBMS all have their own optimization methods, just use a simple many to many scheme. I have a posting system that has millions of posts. Each post can have an infinite number of tags associated with it. Users can create tags which have notes, date created, owner, etc. A tag is almost like a post itself, because people can post notes about the tag. Each tag association has an owner and date, so we can see who added the tag and when. My question is how can I implement this? It has to be fast searching posts by tag, or tags by post. Also, users can add tags to posts by typing the name into a field, kind of like the google search bar, it has to fill in the rest of the tag name for you. I have 3 solutions at the moment, but not sure which is the best, or if there is a better way. Note that I'm not showing the layout of notes since it will be trivial once I get a proper solution for tags. Method 1. Linked list tagId in post points to a linked list in tag_assoc, the application must traverse the list until flink=0 post: id, content, ownerId, date, tagId, notesId tag_assoc: id, tagId, ownerId, flink tag: id, name, notesId Method 2. Denormalization tags is simply a VARCHAR or TEXT field containing a tab delimited array of tagId:ownerId. It cannot be a fixed size. post: id, content, ownerId, date, tags, notesId tag: id, name, notesId Method 3. Toxi (from: http://www.pui.ch/phred/archives/2005/04/tags-database-schemas.html, also same thing here: http://stackoverflow.com/questions/20856/how-do-you-recommend-implementing-tags-or-tagging) post: id, content, ownerId, date, notesId tag_assoc: ownerId, tagId, postId tag: id, name, notesId Method 3 raises the question, how fast will it be to iterate through every single row in tag_assoc? Methods 1 and 2 should be fast for returning tags by post, but for posts by tag, another lookup table must be made. The last thing I have to worry about is optimizing searching tags by name, I have not worked that out yet. I made an ASCII diagram here: http://pastebin.com/f1c4e0e53

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  • PHP5 getrusage() returning incorrect information?

    - by Andrew
    I'm trying to determine CPU usage of my PHP scripts. I just found this article which details how to find system and user CPU usage time (Section 4). However, when I tried out the examples, I received completely different results. The first example: sleep(3); $data = getrusage(); echo "User time: ". ($data['ru_utime.tv_sec'] + $data['ru_utime.tv_usec'] / 1000000); echo "System time: ". ($data['ru_stime.tv_sec'] + $data['ru_stime.tv_usec'] / 1000000); Results in: User time: 29.53 System time: 2.71 Example 2: for($i=0;$i<10000000;$i++) { } // Same echo statements Results: User time: 16.69 System time: 2.1 Example 3: $start = microtime(true); while(microtime(true) - $start < 3) { } // Same echo statements Results: User time: 34.94 System time: 3.14 Obviously, none of the information is correct except maybe the system time in the third example. So what am I doing wrong? I'd really like to be able to use this information, but it needs to be reliable. I'm using Ubuntu Server 8.04 LTS (32-bit) and this is the output of php -v: PHP 5.2.4-2ubuntu5.10 with Suhosin-Patch 0.9.6.2 (cli) (built: Jan 6 2010 22:01:14) Copyright (c) 1997-2007 The PHP Group Zend Engine v2.2.0, Copyright (c) 1998-2007 Zend Technologies

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  • how to import other schema jars when using the scomp tool

    - by MikeJiang
    there is a huge amount of xml schemas for the business, some of them are common types like Money.xsd, Address.xsd, etc, while others are business specific like Customer.xsd, ShippingOrder.xsd, etc. So I decide to compile these schemas into 2 jars, one is commonbeans.jar, the other is businessbeans.jar. I've separated them into different folders. to build the commonbeans.jar is simple, just run "scomp -out commonbeans.jar ....\common*.xsd"; while run "scomp -out businessbeans.jar ....\business*.xsd" is a different story, there are errors say can't find those common types, and run "scomp -out businessbeans.jar ....\business*.xsd ....\business*.xsd" will blindly duplicate all the common types into the businessbeans.jar. so is there any way to link the commonbeans.jar when compile those busimess schemas, maybe something like "scomp -out businessbeans.jar ....\business*.xsd commonbeans.jar". I hope my poor english has expressed my issue!

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  • Database schema for simple stats project

    - by Bubnoff
    Backdrop: I have a file hierarchy of cvs files for multiple locations named by dates they cover ...by month specifically. Each cvs file in the folder is named after the location. eg', folder name: 2010-feb contains: location1.csv location2.csv Each CSV file holds records like this: 2010-06-28, 20:30:00 , 0 2010-06-29, 08:30:00 , 0 2010-06-29, 09:30:00 , 0 2010-06-29, 10:30:00 , 0 2010-06-29, 11:30:00 , 0 meaning of record columns ( column names ): Date, time, # of sessions I have a perl script that pulls the data from this mess and originally I was going to store it as json files, but am thinking a database might be more appropriate long term ...comparing year to year trends ...fun stuff like that. Pt 2 - My question/problem: So I now have a REST service that coughs up json with a test database. My question is [ I suck at db design ], how best to design a database backend for this? I am thinking the following tables would suffice and keep it simple: Location: (PK)location_code, name session: (PK)id, (FK)location_code, month, hour, num_sessions I need to be able to average sessions (plus min and max) for each hour across days of week in addition to days of week in a given month or months. I've been using perl hashes to do this and am trying to decide how best to implement this with a database. Do you think stored procedures should be used? As to the database, depending on info gathered here, it will be postgresql or sqlite. If there is no compelling reason for postgresql I'll stick with sqlite. How and where should I compare the data to hours of operation. I am storing the hours of operation in a yaml file. I currently 'match' the hour in the data to a hash from the yaml to do this. Would a database open simpler methods? I am thinking I would do this comparison as I do now then insert the data. Can be recalled with: SELECT hour, num_sessions FROM session WHERE location_code=LOC1 Since only hours of operation are present, I do not need to worry about it. Should I calculate all results as I do now then store as a stats table for different 'reports'? This, rather than processing on demand? How would this look? Anyway ...I ramble. Thanks for reading! Bubnoff

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  • cannot modify header information puzzler

    - by outofmyleague_lucy
    hi im out of my league i have written what has now become identical code for two sites hosted on different servers. the first worked perfectly and i have therefore used it to compare the second to.from a login for i am directing to a loginaction.php when i include the db_connect.php ie <?php session_start(); include 'db_connect.php'; $user=$_POST['formUser'] $password=$_POST['formPassword']etc ? i am returning cannot modify header information header info already sent, but when i include the content of the db_connect ie <?php session_start(); $connect = mysql_connect("localhost", "user", "pass"); mysql_select_db(db_name, $connection); $user=$_POST['formUser'] $password=$_POST['formPassword']etc ? it works. any ideas? edit - requested error message Warning: Cannot modify header information - headers already sent by (output started at /home/avenncou/public_html/include/db_connect.php:4) in /home/avenncou/public_html/include/loginaction.php on line 14 at line 14 the is a header("Location: {$_SERVER["HTTP_REFERER"]}"); edit - requested db_connect.php <?php $connection = mysql_connect("localhost", "user", "pass");// or die ("Unable to connect!"); mysql_select_db("db", $connection);// or die ("Unable to select database!"); ?> that is all of it (dies commented out in case thats where the error was)!!!

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  • Good or common naming conventions for xsd target namespaces

    - by Anne Schuessler
    I'm looking for some ideas for good naming conventions for xsd target namespaces. Basically I just need to make a definite decision on how to name the target namespace of my xsd so I try to get it right the first time. Changing it later would require changes to another system which is not in my control. Do you have any experience from past XML schema creations on what is a good and working solution? I've tried to find information online, but most examples just use very generic target namespaces like "http://exampleSchema" and similar. I'm actually trying to find some real life examples.

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  • Getting IP/WHOIS information from users clicking ads in Google AdWords?

    - by nctrnl
    I am running a Google AdWords campaign and am wondering if I can get any information from the people who click my ads? I already collect statistics on the website, but I get no referer information from the Google ads in the search network, only from the display network. I am also running Google Analytics on the website but I can't find any relevant information there. P.S: Tag suggestion: google-adwords

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  • FluentNHibernate: Not.Nullable() doesn't affect output schema

    - by alex
    Hello I'm using fluent nhibernate v. 1.0.0.595. There is a class: public class Weight { public virtual int Id { get; set; } public virtual double Value { get; set; } } I want to map it on the following table: create table [Weight] ( WeightId INT IDENTITY NOT NULL, Weight DOUBLE not null, primary key (WeightId) ) Here is the map: public class WeightMap : ClassMap<Weight> { public WeightMap() { Table("[Weight]"); Id(x => x.Id, "WeightId"); Map(x => x.Value, "Weight").Not.Nullable(); } } The problem is that this mapping produces table with nullable Weight column: Weight DOUBLE null Not-nullable column is generated only with default convention for column name (i.e. Map(x = x.Value).Not.Nullable() instead of Map(x = x.Value, "Weight").Not.Nullable()), but in this case there will be Value column instead of Weight: create table [Weight] ( WeightId INT IDENTITY NOT NULL, Value DOUBLE not null, primary key (WeightId) ) I found similiar problem here: http://code.google.com/p/fluent-nhibernate/issues/detail?id=121, but seems like mentioned workaround with SetAttributeOnColumnElement("not-null", "true") is outdated. Does anybody encountered with this problem? Is there a way to specify named column as not-nullable?

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  • How to get an ordered list parsed by XML parser?

    - by Matthias Doringer
    I am using a xsd schema file; there I specified an ordered list. When parsing an XML node of the kind... <myOrderedList> "element_1" "element_2" "element_3" </myOrderedList> (which is valid XML syntax) ...all XML parsers I know parse this as a single node element. Is there a way to get the XML parser parse this list for me (return it as a list or an array or whatever) or do I always have to parse it myself?

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  • Why is rails setting ":null => false" on all my columns in schema.rb?

    - by ryeguy
    Even if I never specify :null => false in my migrations that initially add columns to tables, rails still generates code in schema.rb that specifies the columns as having :null => false. Why is this? If I develop on my box, and then use rake db:schema:load on my production box, I'm going to get very different behavior! Edit: Even if I delete schema.rb and run rake db:schema:dump, it still puts :null => false on the new schema even if it isn't defined like that in the actual database. It seems it can't tell whether or not a column is marked as allowing nulls. I'm using SQLite if that helps.

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  • e-commerce product data/metadata schemas

    - by Shreko
    Trying to figure out how is product data/metadata schema designed. For example, how does an e-commerce site enter a product spec. Does it copy and paste from mfg spec sheet, enters it in their own fields or something else? Here is an example, looking at the D3000 Nikon DSLR Manufacturer: http://nikon.ca/en/Product.aspx?m=17300&disp=Specs futureshop.ca: www.futureshop.ca/en-CA/product/nikon-nikon-d3000-10-2mp-dslr-camera-with-18-55mm-lens-kit-d3000/10128435.aspx?path=865c2348a1542e848982c9dbd9253483en02 memoryexpress.com: www.memoryexpress.com/Products/PID-MX25539%28ME%29.aspx They are all slightly different in order or in parent/child field? What's storage is used for this type of info rdbms or xml?

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  • Information about PTE's (Page Table Entries) in Windows

    - by Patrick
    In order to find more easily buffer overflows I am changing our custom memory allocator so that it allocates a full 4KB page instead of only the wanted number of bytes. Then I change the page protection and size so that if the caller writes before or after its allocated piece of memory, the application immediately crashes. Problem is that although I have enough memory, the application never starts up completely because it runs out of memory. This has two causes: since every allocation needs 4 KB, we probably reach the 2 GB limit very soon. This problem could be solved if I would make a 64-bit executable (didn't try it yet). even when I only need a few hundreds of megabytes, the allocations fail at a certain moment. The second problem is the biggest one, and I think it's related to the maximum number of PTE's (page table entries, which store information on how Virtual Memory is mapped to physical memory, and whether pages should be read-only or not) you can have in a process. My questions (or a cry-for-tips): Where can I find information about the maximum number of PTE's in a process? Is this different (higher) for 64-bit systems/applications or not? Can the number of PTE's be configured in the application or in Windows? Thanks, Patrick PS. note for those who will try to argument that you shouldn't write your own memory manager: My application is rather specific so I really want full control over memory management (can't give any more details) Last week we had a memory overwrite which we couldn't find using the standard C++ allocator and the debugging functionality of the C/C++ run time (it only said "block corrupt" minutes after the actual corruption") We also tried standard Windows utilities (like GFLAGS, ...) but they slowed down the application by a factor of 100, and couldn't find the exact position of the overwrite either We also tried the "Full Page Heap" functionality of Application Verifier, but then the application doesn't start up either (probably also running out of PTE's)

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  • php loop xml data with xsd schema - how do get the data

    - by miholzi
    i try to geht the data from a xml file and i have troubles to get data, for example, how can i get the caaml:locRef value or the caaml:beginPosition value? here is the code so far: /* a big thank you to helderdarocha */ /* – he already helped me yesterday with a part of this code */ $doc = new DOMDocument(); $doc->load('xml/test.xml'); $xpath = new DOMXpath($doc); $xpath->registerNamespace("caaml", "http://caaml.org/Schemas/V5.0/Profiles/BulletinEAWS"); if ($doc->schemaValidate('http://caaml.org/Schemas/V5.0/Profiles/BulletinEAWS/CAAMLv5_BulletinEAWS.xsd')) { foreach ($xpath->query('//caaml:DangerRating') as $key) { echo $key->nodeValue; print_r($key); } } and here ist the print_r from $key DOMElement Object ( [tagName] => caaml:DangerRating [schemaTypeInfo] => [nodeName] => caaml:DangerRating [nodeValue] => 2014-03-03+01:00 2 [nodeType] => 1 [parentNode] => (object value omitted) [childNodes] => (object value omitted) [firstChild] => (object value omitted) [lastChild] => (object value omitted) [previousSibling] => (object value omitted) [nextSibling] => (object value omitted) [attributes] => (object value omitted) [ownerDocument] => (object value omitted) [namespaceURI] => http://caaml.org/Schemas/V5.0/Profiles/BulletinEAWS [prefix] => caaml [localName] => DangerRating [baseURI] => /Applications/MAMP/htdocs/lola/xml/test.xml [textContent] => 2014-03-03+01:00 2 ) 2014-03-04+01:00 2 and here a part of the xml <caaml:DangerRating> <caaml:locRef xlink:href="AT7R1"/> <caaml:validTime> <caaml:TimePeriod> <caaml:beginPosition>2014-03-06T00:00:00+01:00</caaml:beginPosition> <caaml:endPosition>2014-03-06T11:59:59+01:00</caaml:endPosition> </caaml:TimePeriod> </caaml:validTime> <caaml:validElevation> <caaml:ElevationRange uom="m"> <caaml:beginPosition>2200</caaml:beginPosition> </caaml:ElevationRange> </caaml:validElevation> <caaml:mainValue>2</caaml:mainValue> </caaml:DangerRating> <caaml:DangerRating> <caaml:locRef xlink:href="AT7R1"/> <caaml:validTime> <caaml:TimePeriod> thanks!

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  • How to create a user customizable database (like Zoho creator) in Rails?

    - by martjno
    I'm learning Rails, and the target of my experiments is to realize something similar to Zoho Creator, Flexlist or Mytaskhelper, i.e. an app where the user can create his own database schema and views. What's the best strategy to pursue this? I saw something about the Entity-Attribute-Value but I'm not sure whether it's the best strategy or if there is some support in Rails for it. If there was any tutorial in Rails about a similar project it would be great. Probably it's not the easiest star for learning a new language and framework, but it would be something I really plan to do since a long time.

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  • Adding to the schema of a subscribing database.

    - by NTDLS
    Transactional Replication on SQL Server 2005 Enterprise x64 (SP3). I need to add check constraints to a databases that is the target for a replication, but I cannot add the check constraints to the publishing database. The Problem is that the replication process keeps removing my constraints. How do I prevent this?

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  • How to define schema for an ActiveRecord model?

    - by Eric Stanton
    I can find how to define columns only when doing migrations. However i do not need to migrate my model. I want to work with it "virtually". Does AR read columns data only from db? Any way to define columns like in DataMapper? class Post include DataMapper::Resource property :id, Serial property :title, String property :published, Boolean end Now i can play with my model without migrations/connections.

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  • Database schema to store AND, OR relation, association

    - by user455387
    Many thanks for your help on this. In order for an entreprise to get a call for tender it must meet certain requirements. For the first example the enterprise must have a minimal class 4, and have qualification 2 in sector 5. Minimal class is always one number. Qualification can be anything (single, or multiple using AND, OR logical operators) I have created tables in order to map each number to it's given name. Now I need to store requirements in the database. minimal class 4 Sector Qualification 5.2 minimal class 2 Sector Qualifications 3.9 and 3.10 minimal class 3 Sector Qualifications 6.1 or 6.3 minimal class 1 Sector Qualifications (3.1 and 3.2) or 5.6 class Domain < ActiveRecord::Base has_many :domain_classes has_many :domain_sectors has_many :sector_qualifications, :through => :domain_sectors end class DomainClass < ActiveRecord::Base belongs_to :domain end class DomainSector < ActiveRecord::Base belongs_to :domain has_many :sector_qualifications end class SectorQualification < ActiveRecord::Base belongs_to :domain_sector end create_table "domains", :force => true do |t| t.string "name" end create_table "domain_classes", :force => true do |t| t.integer "number" t.integer "domain_id" end create_table "domain_sectors", :force => true do |t| t.string "name" t.integer "number" t.integer "domain_id" end create_table "sector_qualifications", :force => true do |t| t.string "name" t.integer "number" t.integer "domain_sector_id" end

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  • Need inputs in architecting SOA which handles multiple versions of schema

    - by user555400
    Hi, I am working on an assignment where building SOA for an existing application. I am trying to get input from you guys on which is better approach for the SOA application: Here is the requirement: We want to develop SOA application that helps other vendors to integrate with our system. I also understand for some clients we need to bring new fields to support the integration. Solution Needed: Looking for either one SOA application which can handle all the clients to do the integration with our system. Question Is it possible to do so? Because we might have different contracts possibly bringing new fields coming into the contracts. (or) Develop a another SOA service if the service contract changes and have a front gate SOA service to divert the call to the appropriate SOA services based on the version [Probably mentioned in the SOAP header]. If anyone of you guys have handled this type of requirement and know how to handle this problem, that would help me. Thanks, Nazim

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  • using dummy row with NOT NULL to solve DEFAUT NULL

    - by Tony38
    I know having DEFAULT NULLS is not a good practice but I have many optional lookup values which are FK in the system so to solve this issue here is what i am doing: I use NOT NULL for every FK / lookup valve field. I have the first row in every table which is PK id = 1 as a dummy row with just "none" in all the columns. this way I can use NOT NULL in my schema and if needed reference to the none row values which should be null. Is this a good design or any other work arounds?

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