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  • Specify XML schema data type of decimal or blank

    - by Jeremy Stein
    Is there a way in an XML schema to specify that an element may contain either an empty string or a decimal? If I specify the type as xs:decimal like this: <xs:element name="Sample" type="xs:decimal" /> then a blank value would not pass validation: <Sample/> (I realize that the best way to indicate no value would be to not include the element, but I was wondering if there was a way to allow blank or decimal.)

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  • Automatic database schema generation and migration with Perl

    - by pistacchio
    In Ror or Django or web2py you can "describe" a database (as a set of classes that remaps to tables) and the framework (having being provided with a connection string to the desired database) generates the tables, fields, relations and in the case of RoR and web2py it also keeps it up-to-date (eg, removing a class drops the table, adding a property to the class triggers an "alter table add" etc). Is there any Perl module that does the same? Eg, it takes the YAML/XML/JSON description of a database as input and modifies/generates the database schema accordingly?

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  • Any good SQL Anywhere database schema comparison tools?

    - by Lurker Indeed
    Are there any good database schema comparison tools out there that support Sybase SQL Anywhere version 10? I've seen a litany of them for SQL Server, a few for MySQL and Oracle, but nothing that supports SQL Anywhere correctly. I tried using DB Solo, but it turned all my non-unique indexes into unique ones, and I didn't see any options to change that.

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  • Good tool to visualise database schema?

    - by Mat
    Are there any good tools for visualising a pre-existing database schema? I'm using MySQL if it matters. I'm currently using MySQL Workbench to process an SQL create script dump, but it's clunky, slow and a manual process to drag all the tables about (which would be okay if it wasn't so slow).

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  • What is the best schema design for child collection with a "primary" entity

    - by erg39
    Here is the scenario: You have a Persons table with a one-to-many relationship with an Addresses table, where one of the Address rows is the "primary" Address. Is it better in a normalized schema to Use a Persons.PrimaryAddressID to access the "primary" Address for a Person or Use an Addresses.IsPrimary bit column to reference the "primary" Address for a Person via Addresses.PersonID or Other and why?

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  • Schema to support dynamic properties

    - by Johan Fredrik Varen
    Hi people. I'm working on an editor that enables its users to create "object" definitions in real-time. A definition can contain zero or more properties. A property has a name a type. Once a definition is created, a user can create an object of that definition and set the property values of that object. So by the click of a mouse-button, the user should ie. be able to create a new definition called "Bicycle", and add the property "Size" of type "Numeric". Then another property called "Name" of type "Text", and then another property called "Price" of type "Numeric". Once that is done, the user should be able to create a couple of "Bicycle" objects and fill in the "Name" and "Price" property values of each bike. Now, I've seen this feature in several software products, so it must be a well-known concept. My problem started when I sat down and tried to come up with a DB schema to support this data structure, because I want the property values to be stored using the appropriate column types. Ie. a numeric property value is stored as, say, an INT in the database, and a textual property value is stored as VARCHAR. First, I need a table that will hold all my object definitions: Table obj_defs id | name | ---------------- 1 | "Bicycle" | 2 | "Book" | Then I need a table for holding what sort of properties each object definition should have: Table prop_defs id | obj_def_id | name | type | ------------------------------------ 1 | 1 | "Size" | ? | 2 | 1 | "Name" | ? | 3 | 1 | "Price" | ? | 4 | 2 | "Title" | ? | 5 | 2 | "Author" | ? | 6 | 2 | "ISBN" | ? | I would also need a table that holds each object: Table objects id | created | updated | ------------------------------ 1 | 2011-05-14 | 2011-06-15 | 2 | 2011-05-14 | 2011-06-15 | 3 | 2011-05-14 | 2011-06-15 | Finally, I need a table that will hold the actual property values of each object, and one solution is for this table to have one column for each possible value type, such as this: Table prop_vals id | prop_def_id | object_id | numeric | textual | boolean | ------------------------------------------------------------ 1 | 1 | 1 | 27 | | | 2 | 2 | 1 | | "Trek" | | 3 | 3 | 1 | 1249 | | | 4 | 1 | 2 | 26 | | | 5 | 2 | 2 | | "GT" | | 6 | 3 | 2 | 159 | | | 7 | 4 | 3 | | "It" | | 8 | 5 | 3 | | "King" | | 9 | 6 | 4 | 9 | | | If I implemented this schema, what would the "type" column of the prop_defs table hold? Integers that each map to a column name, varchars that simply hold the column name? Any other possibilities? Would a stored procedure help me out here in some way? And what would the SQL for fetching the "name" property of object 2 look like?

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  • Meshing different systems of keys together in XML Schema

    - by Tom W
    Hello SO, I'd like to ask people's thoughts on an XSD problem I've been pondering. The system I am trying to model is thus: I have a general type that represents some item in a hypothetical model. The type is abstract and will be inherited by all manner of different model objects, so the model is heterogeneous. Furthermore, some types exist only as children of other types. Objects are to be given an identifier, but the scope of uniqueness of this identifier varies. Some objects - we will call them P (for Parent) objects - must have a globally unique identifier. This is straightforward and can use the xs:key schema element. Other objects (we can call them C objects, for Child) are children of a P object and must have an identifier that is unique only in the scope of that parent. For example, object P1 has two children, object C1 and C2, and object P2 has one child, object C3. In this system, the identifiers given could be as follows: P1: 1 (1st P object globally) P2: 2 (2nd P object globally) C1: 1 (1st C object of P1) C2: 2 (2nd C object of P1) C3: 1 (1st C object of P2) I want the identity syntax of every model object to be identical if possible, therefore my first pass at implementing is to define a single type: <xs:complexType name="ModelElement"> <xs:attribute name="IDMode" type="IdentityMode"/> <xs:attribute name="Identifier" type="xs:string"/> </xs:complexType> where the IdentityMode is an enumerated value: <xs:simpleType name="IdentityMode"> <xs:restriction base="xs:string"> <xs:enumeration value="Identified"/> <xs:enumeration value="Indexed"/> <xs:enumeration value="None"/> </xs:restriction> </xs:simpleType> Here "Identified" signifies a global identifier, and "Indexed" indicates an identifier local only to the parent. My question is, how do I enforce these uniqueness conditions using unique, key or other schema elements based on the IdentityMode property of the given subtype of ModelElement?

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  • how to hook a callback to click event of star rating control

    - by mohang
    I am using jQuery star rating control found at http://www.fyneworks.com/jquery/star-rating/#tab-Overview . I am using 5 stars, each star having a particular value from 1 to 5. The control is getting displayed and behaving properly. However, I have a requirement of getting the value of the star clicked, immediately after a star is clicked. I do not know how to do it. I appreciate your help.

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  • DC Comics Identifies Krypton on the Star Map

    - by Jason Fitzpatrick
    This week Action Comics Superman #14 hits the stands and DC comics reveals the actual location of Kyrpton, delivered by none other than beloved astrophysicist Neil Tyson. Phil Plait at Bad Astronomy reports on the resolution of fans’ long standing curiosity about the location of Krypton: Well, that’s about to change. DC comics is releasing a new book this week – Action Comics Superman #14 – that finally reveals the answer to this stellar question. And they picked a special guest to reveal it: my old friend Neil Tyson. Actually, Neil did more than just appear in the comic: he was approached by DC to find a good star to fit the story. Red supergiants don’t work; they explode as supernovae when they are too young to have an advanced civilization rise on any orbiting planets. Red giants aren’t a great fit either; they can be old, but none is at the right distance to match the storyline. It would have to be a red dwarf: there are lots of them, they can be very old, and some are close enough to fit the plot. I won’t keep you in suspense: the star is LHS 2520, a red dwarf in the southern constellation of Corvus (at the center of the picture here). It’s an M3.5 dwarf, meaning it has about a quarter of the Sun’s mass, a third its diameter, roughly half the Sun’s temperature, and a luminosity of a mere 1% of our Sun’s. It’s only 27 light years away – very close on the scale of the galaxy – but such a dim bulb you need a telescope to see it at all (for any astronomers out there, the coordinates are RA: 12h 10m 5.77s, Dec: -15° 4m 17.9 s). 6 Ways Windows 8 Is More Secure Than Windows 7 HTG Explains: Why It’s Good That Your Computer’s RAM Is Full 10 Awesome Improvements For Desktop Users in Windows 8

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  • Faking a dynamic schema in Core Data?

    - by Gouldsc
    From reading the Apple Docs on Core Data, I've learned that you should not use Core Data when you need a dynamic schema. If I wanted to provide the user the ability to create their own properties, in a core data model would it work if I created some "dummy" attributes like "custom decimal 1", "custom decimal 2", "custom text 1", "custom text 2" etc that the user could name and use for their own purposes? Obviously this won't work for relationships, but for simple properties it seems like a reasonable workaround. Will creating a bunch of dummy attributes on my entities that go unused by most users noticeably decrease performance for them? Have any of you tried something like this? Thanks!

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  • Star Trek inspired home automation visualisation

    - by Zak McKracken
    I’ve always been a more or less active fan of Star Trek. During the construction phase of my house I started coding a GUI for controlling the house which has an EIB. Just for fun I designed a version inspired by the LCARS design used in Star Trek TNG and showed this to my wife. I showed her several designs before but this was the only one, she really liked. So I decided to go on with this. I started a C# WinForms application. The software runs on a wall mounted Shuttle Barebone-PC. First plan was an industrial panel-pc but the processor was too slow. The now-used Atom is ok. I started with the LCARS-controls found on Codeproject. Since the classic LCARS design divides the screen into two parts this tended to be impracticable, so I used my own design For now the software is able to: Switch lights/wall outlets Show current temperatures for all room controllers Show outside temperature with a 24h trend chart Show the status of the two heat pumps Provide an alarm clock (e.g. for cooking) Play internet radio streams Control absence Mute the door bell Speak status messages via speech synthesis For now, I’m working on an integration of my electric meter. The main heat pump and the electric meter are connected to my LAN. I also tried some speech recognition, but I’ve problems with the microphone. I't’s working when you are right in front of the PC, but not far away, let’s say on the other side of the room. So this is the main view. The table displays raw values which are sent over the EIB – completely useless but looks great For each floor I have a different view. Here you can see the temperatures and check the status of the lights (the buttons are blinking when a light is switched on) This is the view for the heat pump:   Next step would be to integrate a control of my squeezebox server (I use different Squeezeboxes through the house as a multiroom audio solution)

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  • MongoDB Schema Design - Real-time Chat

    - by Nick
    I'm starting a project which I think will be particularly suited to MongoDB due to the speed and scalability it affords. The module I'm currently interested in is to do with real-time chat. If I was to do this in a traditional RDBMS I'd split it out into: Channel (A channel has many users) User (A user has one channel but many messages) Message (A message has a user) The the purpose of this use case, I'd like to assume that there will be typically 5 channels active at one time, each handling at most 5 messages per second. Specific queries that need to be fast: Fetch new messages (based on an bookmark, time stamp maybe, or an incrementing counter?) Post a message to a channel Verify that a user can post in a channel Bearing in mind that the document limit with MongoDB is 4mb, how would you go about designing the schema? What would yours look like? Are there any gotchas I should watch out for?

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  • An Interview with JavaOne Rock Star Martijn Verburg

    - by Janice J. Heiss
    An interview with JavaOne Rock Star Martijn Verburg, by yours truly, titled “Challenging the Diabolical Developer: A Conversation with JavaOne Rock Star Martijn Verburg,” is now up on otn/java. Verburg, one of the leading movers and shakers in the Java community, is well known for his ‘diabolical developer” talks at JavaOne where he uncovers some of the worst practices that Java developers are prone to. He mentions a few in the interview: * “A lack of communication: Software development is far more a social activity than a technical one; most projects fail because of communication issues and social dynamics, not because of a bad technical decision. Sadly, many developers never learn this lesson.* No source control: Some developers simply store code in local file systems and e-mail the code in order to integrate their changes; yes, this still happens.* Design-driven design: Some developers are inclined to cram every design pattern from the Gang of Four (GoF) book into their projects. Of course, by that stage, they've actually forgotten why they're building the software in the first place.” He points to a couple of core assumptions and confusions that lead to trouble: “One is that developers think that the JVM is a magic box that will clean up their memory and make their code run fast, as well as make them cups of coffee. The JVM does help in a lot of cases, but bad code can and will still lead to terrible results! The other trend is to try to force Java (the language) to do something it's not very good at, such as rapid Web development. So you get a proliferation of overly complex frameworks, libraries, and techniques trying to get around the fact that Java is a monolithic, statically typed, compiled, OO environment. It's not a Golden Hammer!” Verburg has many insightful things to say about how to keep a Java User Group (JUG) going, about the “Adopt a JSR” program, bugathons, and much more. Check out the article here.

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  • One Step-Ahead A-Star

    - by Jonathan Dickinson
    I am attempting to create a server-centric RTS (as opposed to usual parallel synchronised simulation route of most RTS games today) - however I am still leveraging the discreet N-turns-ahead paradigm discussed by one of the AOE developers on Gamasutra. I have [possibly questionably?] decided that the path finding should only ever find the next cell the entity needs to move to, and was wondering if anyone has any clever ideas on how to optimize the algorithm for this specific scenario - or any other ideas on how to keep the pathfinding as lean as possible on the server. I have investigated a few possible algorithms but could only come up with one appropriation: Tiered A-Star - Relatively large T1 tiles, work out (and cache) each cell as you enter it. Other than that: doing the full A-Star pass and caching the entire path, which might use too much memory if a large amount of units are present. I know about the existence of naive progressive pathfinding algorithms (if you hit a block, turn in the direction closer to your target etc.) but they suffer from infinite feedback loops - and very poor pathing even if visited blocks are memorised. Not an option. Many thanks.

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  • Good conventions for embedding schema of a flat file

    - by Ville Koskinen
    We receive lots of data as flat files: delimitted or just fixed length records. It's sometimes hard to find out what the files actually contain. Are there any well established practices for embedding the schema of the file to the beginning or the end of a file to make the file self-explanatory? Just to get an idea, imagine something like this: <data name=test records=2 type=fixed> <field name=foo start=0 length=2 type=numeric> <field name=bar start=2 length=4 type=text> </data> 11test 12ing We would parse the xml in the beginning and use it for reading the records.

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  • Schema Based Code Completion for NetBeans Platform Applications

    - by Geertjan
    Toni's recent blog entry provides, among several other interesting things, instructions for something I've been wanting to cover for a long time, which is schema based code completion: The above is a sample I created via Toni's tutorial, using the schema described here: http://www.w3schools.com/schema/schema_example.asp The support for the Navigator ain't bad either, especially considering I didn't do any coding at all to get all this: And here's where you can find the whole sample: http://java.net/projects/nb-api-samples/sources/api-samples/show/versions/7.2/misc/ShipOrder

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  • xs:choice unbounded list

    - by Matt
    I want to define an XSD schema for an XML document, example below: <?xml version="1.0" encoding="utf-8"?> <view xmlns="http://localhost/model_data" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://localhost/model_data XMLSchemaView.xsd" path="wibble" id="wibble"> <text name="PageTitle">Homepage</text> <text name="Keywords">home foo bar</text> <image name="MainImage"> <description>lolem ipsum</description> <title>i haz it</title> <url>/images/main-image.jpg</url> <type>image/jpeg</type> <alt>alt text for image</alt> <width>400</width> <height>300</height> </image> <link name="TermsAndConditionsLink"> <url>/tnc.html</url> <title>Terms and Conditions</title> <target>_blank</target> </link> </view> There's a view root element and then an unknown number of field elements (of various types). I'm using the following XSD schema: <?xml version="1.0" encoding="utf-8"?> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns="http://localhost/model_data" targetNamespace="http://localhost/model_data" id="XMLSchema1"> <xs:element name="text" type="text_field"/> <xs:element name="view" type="model_data"/> <xs:complexType name="model_data"> <xs:choice maxOccurs="unbounded"> <xs:element name="text" type="text_field"/> <xs:element name="image" type="image_field"/> <xs:element name="link" type="link_field"/> </xs:choice> <xs:attribute name="path" type="xs:string"/> <xs:attribute name="id" type="xs:string"/> </xs:complexType> <xs:complexType name="image_field"> <xs:all> <xs:element name="description" type="xs:string"/> <xs:element name="title" type="xs:string"/> <xs:element name="type" type="xs:string"/> <xs:element name="url" type="xs:string"/> <xs:element name="alt" type="xs:string"/> <xs:element name="height" type="xs:int"/> <xs:element name="width" type="xs:int"/> </xs:all> <xs:attribute name="name" type="xs:string"/> </xs:complexType> <xs:complexType name="text_field"> <xs:simpleContent> <xs:extension base="xs:string"> <xs:attribute name="name" type="xs:string"/> </xs:extension> </xs:simpleContent> </xs:complexType> <xs:complexType name="link_field"> <xs:all> <xs:element name="target" type="xs:string"/> <xs:element name="title" type="xs:string"/> <xs:element name="url" type="xs:string"/> </xs:all> <xs:attribute name="name" type="xs:string"/> </xs:complexType> </xs:schema> This looks like it should work to me, but it doesn't and I always get the following error: Element <text> is not allowed under element <view>. Reason: The following elements are expected at this location (see below) <text> <image> <link> Error location: view / text Details cvc-model-group: Element <text> unexpected by type 'model_data' of element <view>. cvc-elt.5.2.1: The element <view> is not valid with respect to the actual type definition 'model_data'. I've never really used XSD schemas before, so I'd really appreciate it if someone could point out where I'm going wrong.

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  • Inheritance in XML Schema definition (XSD) for Java objects

    - by bguiz
    Hi, I need to create an XML schema definition (XSD) that describes Java objects. I was wondering how to do this when the objects in question inherit from a common base class with a type parameter. public abstract class Rule<T> { ... } public abstract class TimeRule extends Rule<XTime> { ... } public abstract class LocationRule extends Rule<Location> { ... } public abstract class IntRule extends Rule<Integer> { ... } .... (where XTime and Location are custom classes define elsewhere) How would I go about constructing an XSD that such that I can have XML nodes that represent each of the subclasses of Rule<T> - without the XSD for each of them repeating their common contents? Thank you!

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