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  • large databases in sqlite - file size considerations?

    - by Gj
    I'm using a sqlite db which is very convenient and seems to meet all of my needs at this point. Currently my db size is <50MB, but I now need to add a new table which will store large text blobs, which will cause the db to reach up to 5GB within the next year. Would sqlite be able to deal with a 5GB db size? Any caveats to that, compared with say mysql?

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  • What is the corrrect way to increment a field making up part of a composit key

    - by Tr1stan
    I have a bunch of tables whose primary key is made up of the foreign keys of other tables (Composite key). Therefore for example the attributes (as a very cut down version) might look like this: A[aPK, SomeFields] 1:M B[bPK, aFK, SomeFields] 1:M C[cPK, bFK, aFK, SomeFields] as data this could look like: A[aPK, SomeFields]: 1, Foo 2, Bar B[bPK, aFK, SomeFields]: 1, 1, FooData1 2, 1, FooData2 1, 2, BarData1 2, 2, BarData2 C[cPK, bFK, aFK, SomeFields]: 1, 1, 1, FooData1More 2, 1, 1, FooData1More 1, 2, 1, FooData2More 2, 2, 1, FooData2More 1, 1, 2, BarData1More 2, 1, 2, BarData1More 1, 2, 2, BarData2More 2, 2, 2, BarData2More I've got this running in a MSSQL DBMS and I'm looking for the best way to increment the left most column, in each table when a new tuple is added to it. I can't use the Auto Increment Identity Specification option as that has no idea that it is part of a composite key. I also don't want to use any aggregate function such as: MAX(field)+1 as this will have adverse affects with multiple users inputting data, rolling back etc. There might however be a nice trigger based option here, but I'm not sure. This must be a common issue so I'm hoping that someone has a lovely solution. As a side which may or may not affect the answer, I'm using Entity Framework 1.0 as my ORM, within a c# MVC application.

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  • NoSQL for filesystem storage organization and replication?

    - by wheaties
    We've been discussing design of a data warehouse strategy within our group for meeting testing, reproducibility, and data syncing requirements. One of the suggested ideas is to adapt a NoSQL approach using an existing tool rather than try to re-implement a whole lot of the same on a file system. I don't know if a NoSQL approach is even the best approach to what we're trying to accomplish but perhaps if I describe what we need/want you all can help. Most of our files are large, 50+ Gig in size, held in a proprietary, third-party format. We need to be able to access each file by a name/date/source/time/artifact combination. Essentially a key-value pair style look-up. When we query for a file, we don't want to have to load all of it into memory. They're really too large and would swamp our server. We want to be able to somehow get a reference to the file and then use a proprietary, third-party API to ingest portions of it. We want to easily add, remove, and export files from storage. We'd like to set up automatic file replication between two servers (we can write a script for this.) That is, sync the contents of one server with another. We don't need a distributed system where it only appears as if we have one server. We'd like complete replication. We also have other smaller files that have a tree type relationship with the Big files. One file's content will point to the next and so on, and so on. It's not a "spoked wheel," it's a full blown tree. We'd prefer a Python, C or C++ API to work with a system like this but most of us are experienced with a variety of languages. We don't mind as long as it works, gets the job done, and saves us time. What you think? Is there something out there like this?

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  • Advantage Data Architect doesn't accept 'output to', are there any other options for outputting a ta

    - by likesalmon
    I'm trying to output the results of a SELECT query to a tab delimited text file in Advantage Data Architect. I know I can use the 'Export to' feature to do this, but there are a lot of tables and that is going to take forever. I would rather use the SQL editor, but I found out it does not accept the OUTPUT TO argument, even though that command is part of Sybase SQL. I would like to do this: SELECT * FROM tablename; OUTPUT TO 'C:/ExportDirectory' DELIMITED BY '\t' FORMAT TEXT; Is there another way?

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  • MySQL Table structure of thumb UP & DOWN for comments system ?

    - by Axel
    Hello, i already created a table for comments but i want to add the feature of thumb Up and Down for comments like Digg and Youtube, i use php & mysql and i'm wondering What's the best table scheme to implement that so comments with many likes will be on the top. This is my current comments table : comments(id,user,article,comment,stamp) Note: Only registred will be able to vote, so there isn't need to restrict the votes by IP Thanks

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  • top-k selection/merge

    - by tcurdt
    I have n sorted lists. These lists are quite long (300000+ tuples). Selecting the top 10 of the individual lists is of course trivial - they are right at the head of the lists. Where it gets more interesting is when I want the top 10 of all the sorted lists. The question is whether there is an algorithm to calculate the combined top 10 having the correct order while cutting off the long tail of the lists. The goal is to reduce the required space. And if there is: How does one find the limit where is is safe to cut? Note: The actual counts are not important. Only the order is.

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  • select for update with ruby oci8

    - by ash34
    how do I do a 'select for update' and then 'update' the row using ruby oci8. I have two fields counter1 and counter2 in a table which has only 1 record. I want to select the values from this table and then increment them by locking the row using select for update. thanks.

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  • Mysql random rows

    - by n00b
    please read the whole question... 90% of you dont seem to do that and some of you only read the title obviously... and if you dont know the solution, dont answer - i wont have to downvote you -.-'' im entertaining the idea of getting random rows directly from mysql. what i found was SELECT * FROM tablename WHERE somefield='something' ORDER BY RAND() LIMIT 5 but even i see how slow that would be.. is the only way to do this doing something like SELECT * FROM tablename WHERE somefield='something' LIMIT RAND(aincrementvalue-5), 1 5 times? or is there a way that i with my little knowlege of databases cant come up with ? (no i dont want random indexes. i hate the idea of them...) @commenters - please first look, then think, then look again, think again and then post. i wont point fingers but i dislike stupid comments and why i think random indexes are a nasty hack ? it doesnt give you random results. it gives you x results from a random index in a predefined order its like a gapless id only in the wrong order if you fetch by 1 row and get true randomness you fall back to my method but with an additional junk field finally the reason the field exists is only to serve as a helper to something that can be done without it with almost same performance (but the quality (randomness) is better), so it is a nasty hack ;) i solved it, look @ my answer... if you think its incorrect please tell me :)

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  • Team working on Drupal - Tips

    - by fighella
    I am working on a Drupal site with a few friends. Obviously we can Version control the code... but what do we do to keep each others databases in check? I have managed to get all the theming into files (contemplate etc), but ideally my views settings, menu settings would be in line also... (Not worried about Content either way as we're just building the framework) Any suggestions?

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  • Inheritance in tables - structure problem

    - by Naor
    I have 3 types of users in my system. each type has different information I created the following tables: BaseUser(base_user_id, username, password, additional common data) base_user_id is PK and Identity UserType1(user_id, data related to type1 only) user_id is PK and FK to base_user_id UserType2(user_id, data related to type2 only) user_id is PK and FK to base_user_id UserType3(user_id, data related to type3 only) user_id is PK and FK to base_user_id Now I have relation from each type of user to warehouses table. Users from type1 and type2 should have only warehouse_id and users from type3 should have warehouse_id and customer_id. I thought about this structure: WarehouseOfUser(base_user_id,warehouse_id) base_user_id is FK to base_user_id in BaseUser WarehouseOfTyp3User(base_user_id,warehouse_id, customer_id) base_user_id is FK to base_user_id in BaseUser The problem is that such structure allows 2 things I want to prevent: 1. add to WarehouseOfTyp3User data of user from type2 or type1. 2. add to WarehouseOfUser data of user from type3. what is the best structure for such case?

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  • How to use multiple database in a PHP web application?

    - by Harish
    I am making a PHP web Application in which i am using MySQL as database server, i want to make backup of some tables from one database to another database(with that tables in it). i have created two different connection, but the table is not updated. $dbcon1 = mysql_connect(DB_SERVER,DB_USER,DB_PASSWORD) or die(mysql_error()); $dbase1 = mysql_select_db(TEMP_DB_NAME,$dbcon)or die(mysql_error()); $query1=mysql_query("SELECT * FROM emp"); while($row = mysql_fetch_array($query1, MYSQL_NUM)) { $dbcon2 = mysql_connect(DB_SERVER,DB_USER,DB_PASSWORD) or die(mysql_error()); $dbase2 = mysql_select_db(TEMP_DB_NAME2,$dbcon)or die(mysql_error()); mysql_query("INSERT INTO backup_emp VALUES(null,'$row[1]',$row[2])"); mysql_close($dbcon2); } the code above is taking the data of emp from first database, and updataing it into another backup_emp table of another database. the code is not working properly, is there any other way of doing this...please help.

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  • Search sort by parameter match count in the query? PostgreSQL

    - by Ben Dauphinee
    I am working on a search query in PostgreSQL, and one of the things I do is sort my query results by the number of parameters matched. I have no clue how this can be done. Does anyone have a suggestion or solution? Table brand color type engine Ford Blue 4-door V8 Maserati Blue 2-door V12 Saturn Green 4-door V8 GM Yellow 1-door V4 Current Query SELECT brand FROM table WHERE color = 'Blue' or type = '4-door' or engine = 'V8' Result Should Be Ford (3 match) Saturn (2 match) Maserati (1 match)

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  • MongoMapper: how do I create a model like this

    - by Vladimir R
    Suppose we have two models, Task and User. So a user can have many tasks and tasks should be able to have many users too. But, a task should also have a unique creator who is also a user. Exemple: A task in this context is like this: Task ID, Task Creator, Users who should do the task User_1 creates a task and he is then the creator. User_1 specifies User_2 and User_3 as users who should do the task. So these two last users are not creators of task. How do I create this models so that if I have a task object, I can find it's creator and users who should complete it. And how do I do, if I have a user, to find all tasks he created and all tasks he should complete. Thank you.

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  • Error in connection in ruby.

    - by piemesons
    require 'rubygems' require 'mysql' db = Mysql.connect('localhost', 'root', '', 'mohit') //db.rb:4: undefined method `connect' for Mysql:Class (NoMethodError) //undefined method `real_connect' for Mysql:Class (NoMethodError) db.query("CREATE TABLE people ( id integer primary key, name varchar(50), age integer)") db.query("INSERT INTO people (name, age) VALUES('Chris', 25)") begin query = db.query('SELECT * FROM people') puts "There were #{query.num_rows} rows returned" query.each_hash do |h| puts h.inspect end rescue puts db.errno puts db.error end error i am geting is: undefined method `connect' for Mysql:Class (NoMethodError) OR undefined method `real_connect' for Mysql:Class (NoMethodError) EDIT return value of Mysql.methods ["private_class_method", "inspect", "name", "tap", "clone", "public_methods", "object_id", "__send__", "method_defined?", "instance_variable_defined?", "equal?", "freeze", "extend", "send", "const_defined?", "methods", "ancestors", "module_eval", "instance_method", "hash", "autoload?", "dup", "to_enum", "instance_methods", "public_method_defined?", "instance_variables", "class_variable_defined?", "eql?", "constants", "id", "instance_eval", "singleton_methods", "module_exec", "const_missing", "taint", "instance_variable_get", "frozen?", "enum_for", "private_method_defined?", "public_instance_methods", "display", "instance_of?", "superclass", "method", "to_a", "included_modules", "const_get", "instance_exec", "type", "<", "protected_methods", "<=>", "class_eval", "==", "class_variables", ">", "===", "instance_variable_set", "protected_instance_methods", "protected_method_defined?", "respond_to?", "kind_of?", ">=", "public_class_method", "to_s", "<=", "const_set", "allocate", "class", "new", "private_methods", "=~", "tainted?", "__id__", "class_exec", "autoload", "untaint", "nil?", "private_instance_methods", "include?", "is_a?"] return value of Mysql.methods(false) is []... blank array

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  • ResultSet and aggregation

    - by kachanov
    Ok, I admit my situation is special There is a data system that supports SQL-92 and JDBC interface However the SQL requets are pretty expensive, and in my application I need to retreive the same data multiple times and aggregate it ("group by") on different fields to show different dimensions of the same data. For example on one screen I have three tables that show the same set or records but aggregated by City (1st grid), by Population (2nd grid), by number of babies (3rd grid) This amounts to 3 SQL queries (which is very slow), UNLESS anyone of you can suggest any idea any library from apache commons or from google code, so that I can select all records into ResultSet and get 3 arrays of data group by different fields from this single ResultSet. Am I'm missing some obvious and unexpected solution to this problem?

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  • How to build a SQL statement when any combination of user input to the table is possible?

    - by Greg McNulty
    Example: the user fills in everything but the product name. I need to search on what is supplied, so in this case everything but productName= This example could be for any combination of input. Is there a way to do this? Thanks. $name = $_POST['n']; $cat = $_POST['c']; $price = $_POST['p']; if( !($name) ) { $name = some character to select all? } $sql = "SELECT * FROM products WHERE productCategory='$cat' and productName='$name' and productPrice='$price' "; EDIT Solution does not have to protect from attacks. Specifically looking at the dynamic part of it.

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  • Table for each region in MySQL

    - by King Wu
    There are four regions with more than one million records total. Should I create a table with a region column or a table for each region and combine them to get the top ranks? If I combine all four regions, none of my columns will be unique so I will need to also add an id column for my primary key. Otherwise, name, accountId & characterId would be candidate keys or should I just add an id column anyways. Table: ---------------------------------------------------------------- | name | accountId | iconId | level | characterId | updateDate | ----------------------------------------------------------------

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  • Select distinct users with referrals

    - by Mark
    I have a bunch of Users. Since Django doesn't really let me extend the default User model, they each have Profiles. The Profiles have a referred_by field (a FK to User). I'm trying to get a list of Users with = 1 referral. Here's what I've got so far Profile.objects.filter(referred_by__isnull=False).values_list('referred_by', flat=True) Which gives me a list of IDs of the users who have referrals... but I need it to be distinct, and I want the User object, not their ID. Or better yet, it would be nice if it could return the number of referrals a user has. Any ideas?

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