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  • Web Shop Schema - Document Db

    - by Maxem
    I'd like to evaluate a document db, probably mongo db in an ASP.Net MVC web shop. A little reasoning at the beginning: There are about 2 million products. The product model would be pretty bad for rdbms as there'd be many different kinds of products with unique attributes. For example, there'd be books which have isbn, authors, title, pages etc as well as dvds with play time, directors, artists etc and quite a few more types. In the end, I'd have about 9 different products with a combined column count (counting common columns like title only once) of about 70 to 100 whereas each individual product has 15 columns at most. The three commonly used ways in RDBMS would be: EAV model which would have pretty bad performance characteristics and would make it either impractical or perform even worse if I'd like to display the author of a book in a list of different products (think start page, recommended products etc.). Ignore the column count and put it all in the product table: Although I deal with somewhat bigger databases (row wise), I don't have any experience with tables with more than 20 columns as far as performance is concered but I guess 100 columns would have some implications. Create a table for each product type: I personally don't like this approach as it complicates everything else. C# Driver / Classes: I'd like to use the NoRM driver and so far I think i'll try to create a product dto that contains all properties (grouped within detail classes like book details, except for those properties that should be displayed on list views etc.). In the app I'll use BookBehavior / DvdBehaviour which are wrappers around a product dto but only expose the revelent Properties. My questions now: Are my performance concerns with the many columns approach valid? Did I overlook something and there is a much better way to do it in an RDBMS? Is MongoDb on Windows stable enough? Does my approach with different behaviour wrappers make sense?

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  • Duplicate partitioning key performance impact

    - by Anshul
    I've read in some posts that having duplicate partitioning key can have a performance impact. I've two tables like: CREATE TABLE "Test1" ( CREATE TABLE "Test2" ( key text, key text, column1 text, name text, value text, age text, PRIMARY KEY (key, column1) ... ) PRIMARY KEY (key, name,age) ) In Test1 column1 will contain column name and value will contain its corresponding value.The main advantage of Test1 is that I can add any number of column/value pairs to it without altering the table by just providing same partitioning key each time. Now my question is how will each of these table schema's impact the read/write performance if I've millions of rows and number of columns can be upto 50 in each row. How will it impact the compaction/repair time if I'm writing duplicate entries frequently?

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  • Fact table with multiple facts

    - by Jeff Meatball Yang
    I have a dimension (SiteItem) has two important facts: perUserClicks perBrowserClicks however, within this dimension, I have groups of dimensions based on an attribute column (let's call the groups AboveFoldItems, LeftNavItems, OnTheFlyItems, etc.) each have more facts that are specific to that group: AboveFoldItems: eyeTime, loadTime LeftNavItems: mouseOverTime OnTheFlyItems: doesn't have any extra, but may in the future Is the following fact table schema ok? DateKey SessionKey SiteItemKey perUserClicks perBrowserClicks eyeTime loadTime mouseOverTime It seems a little wasteful since only some columns pertain to some dimension keys (the irrelevant facts are left NULL). But... this seems like it would be a common problem, so there should be a common solution for this, right?

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  • Validating XML tag by tag

    - by Greatful
    Hi All I'm having some issues validating some XML against a Schema, using .net and C#. I am using XmlReaderSettings with the ValidationEventHandler. However, this seems to stop catching errors after it has encountered the first error at a particular level within the XML file, instead of checking the next tag at the same level, so basically it does not check each and every tag within the XML file instead skipping a level when it has found an error. I was hoping to get some advice from somebody who has successfully accomplished this type of validation. Thanks very much

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  • Correct way to give users access to additional schemas in Oracle

    - by Jacob
    I have two users Bob and Alice in Oracle, both created by running the following commands as sysdba from sqlplus: create user $blah identified by $password; grant resource, connect, create view to $blah; I want Bob to have complete access to Alice's schema (that is, all tables), but I'm not sure what grant to run, and whether to run it as sysdba or as Alice. Happy to hear about any good pointers to reference material as well -- don't seem to be able to get a good answer to this from either the Internet or "Oracle Database 10g The Complete Reference", which is sitting on my desk.

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  • What xsd will let an element have itself as a sub element infinitely?

    - by David Basarab
    How can I create an xsd to give me this type of xml structure that can go on infinitely? <?xml version="1.0" encoding="utf-8" ?> <SampleXml> <Items> <Item name="SomeName" type="string"> This would be the value </Item> <Item name="SecondName" type="string"> This is the next string </Item> <Item name="AnotherName" type="list"> <Items> <Item name="SubName" type="string"> A string in a sub list </Item> <Item name="SubSubName" type="list"> <Items> <Item name="HowDoI" type="string"> How do I keep this going infinately? </Item> </Items> </Item> </Items> </Item> </Items> </SampleXml> The only solution I have found has been to just repeat in the xsd as many times as I am willing to copy. Like below. <?xml version="1.0" encoding="utf-8"?> <xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:element name="SampleXml"> <xs:complexType> <xs:sequence> <xs:element name="Items"> <xs:complexType> <xs:sequence> <xs:element maxOccurs="unbounded" name="Item"> <xs:complexType mixed="true"> <xs:sequence minOccurs="0"> <xs:element name="Items"> <xs:complexType> <xs:sequence> <xs:element maxOccurs="unbounded" name="Item"> <xs:complexType mixed="true"> <xs:sequence minOccurs="0"> <xs:element name="Items"> <xs:complexType> <xs:sequence> <xs:element name="Item"> <xs:complexType> <xs:simpleContent> <xs:extension base="xs:string"> <xs:attribute name="name" type="xs:string" use="required" /> <xs:attribute name="type" type="xs:string" use="required" /> </xs:extension> </xs:simpleContent> </xs:complexType> </xs:element> </xs:sequence> </xs:complexType> </xs:element> </xs:sequence> <xs:attribute name="name" type="xs:string" use="required" /> <xs:attribute name="type" type="xs:string" use="required" /> </xs:complexType> </xs:element> </xs:sequence> </xs:complexType> </xs:element> </xs:sequence> <xs:attribute name="name" type="xs:string" use="required" /> <xs:attribute name="type" type="xs:string" use="required" /> </xs:complexType> </xs:element> </xs:sequence> </xs:complexType> </xs:element> </xs:sequence> </xs:complexType> </xs:element> </xs:schema>

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  • Migrate Data and Schema from MySQL to MSSQL

    - by colithium
    Are there any free solutions for automatically migrating a database from MySQL to MSSQL Server that "just works"? I've been attempting this simple (at least I thought so) task all day now. I've tried: MSSQL Server Management Studio's Import Data feature Create an empty database Tasks - Import Data... .NET Framework Data Provider for Odbc Valid DSN (verified it connects) Copy data from one or more tables or views Check 1 VERY simple table Click Preview Get Error: The preview data could not be retrieved. ADDITIONAL INFORMATION: ERROR [42000] [MySQL][ODBC 5.1 Driver][mysqld-5.1.45-community]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 '"table_name"' at line 1 (myodbc5.dll) A similar error occurs if I go through the rest of the wizard and perform the operation. The failed step is "Setting Source Connection" the error refers to retrieving column information and then lists the above error. It can retrieve column information just fine when I modify column mappings so I really don't know what the issue is. I've also tried getting various MySql tools to output ddl statements that MSSQL understand but haven't succeeded. I've tried with MySQL v5.1.11 to SQL Server 2005 and with MySQL v5.1.45 to SQL Server 2008 (with ODBC drivers 3.51.27.00 and 5.01.06.00 respectively)

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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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  • 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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  • 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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  • 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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  • 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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  • Migrate Data and Schema from MySQL to SQL Server

    - by colithium
    Are there any free solutions for automatically migrating a database from MySQL to SQL Server Server that "just works"? I've been attempting this simple (at least I thought so) task all day now. I've tried: SQL Server Management Studio's Import Data feature Create an empty database Tasks - Import Data... .NET Framework Data Provider for Odbc Valid DSN (verified it connects) Copy data from one or more tables or views Check 1 VERY simple table Click Preview Get Error: The preview data could not be retrieved. ADDITIONAL INFORMATION: ERROR [42000] [MySQL][ODBC 5.1 Driver][mysqld-5.1.45-community]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 '"table_name"' at line 1 (myodbc5.dll) A similar error occurs if I go through the rest of the wizard and perform the operation. The failed step is "Setting Source Connection" the error refers to retrieving column information and then lists the above error. It can retrieve column information just fine when I modify column mappings so I really don't know what the issue is. I've also tried getting various MySql tools to output ddl statements that SQL Server understand but haven't succeeded. I've tried with MySQL v5.1.11 to SQL Server 2005 and with MySQL v5.1.45 to SQL Server 2008 (with ODBC drivers 3.51.27.00 and 5.01.06.00 respectively)

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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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  • 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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  • 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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  • 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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  • 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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