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  • Hibernate naturalID

    - by DD
    Hibernate doesnt seem to generate a notnull constraint on a field I marked as naturalID. Is this normal? @MappedSuperclass public class AbstractDomainObject extends PersistentObject { @NaturalId private String code; DB Schema: CONSTRAINT SYS_CT_47 UNIQUE(CODE) There is no not null constraint here.

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  • Can MySQL reasonably perform queries on billions of rows?

    - by haxney
    I am planning on storing scans from a mass spectrometer in a MySQL database and would like to know whether storing and analyzing this amount of data is remotely feasible. I know performance varies wildly depending on the environment, but I'm looking for the rough order of magnitude: will queries take 5 days or 5 milliseconds? Input format Each input file contains a single run of the spectrometer; each run is comprised of a set of scans, and each scan has an ordered array of datapoints. There is a bit of metadata, but the majority of the file is comprised of arrays 32- or 64-bit ints or floats. Host system |----------------+-------------------------------| | OS | Windows 2008 64-bit | | MySQL version | 5.5.24 (x86_64) | | CPU | 2x Xeon E5420 (8 cores total) | | RAM | 8GB | | SSD filesystem | 500 GiB | | HDD RAID | 12 TiB | |----------------+-------------------------------| There are some other services running on the server using negligible processor time. File statistics |------------------+--------------| | number of files | ~16,000 | | total size | 1.3 TiB | | min size | 0 bytes | | max size | 12 GiB | | mean | 800 MiB | | median | 500 MiB | | total datapoints | ~200 billion | |------------------+--------------| The total number of datapoints is a very rough estimate. Proposed schema I'm planning on doing things "right" (i.e. normalizing the data like crazy) and so would have a runs table, a spectra table with a foreign key to runs, and a datapoints table with a foreign key to spectra. The 200 Billion datapoint question I am going to be analyzing across multiple spectra and possibly even multiple runs, resulting in queries which could touch millions of rows. Assuming I index everything properly (which is a topic for another question) and am not trying to shuffle hundreds of MiB across the network, is it remotely plausible for MySQL to handle this? UPDATE: additional info The scan data will be coming from files in the XML-based mzML format. The meat of this format is in the <binaryDataArrayList> elements where the data is stored. Each scan produces = 2 <binaryDataArray> elements which, taken together, form a 2-dimensional (or more) array of the form [[123.456, 234.567, ...], ...]. These data are write-once, so update performance and transaction safety are not concerns. My naïve plan for a database schema is: runs table | column name | type | |-------------+-------------| | id | PRIMARY KEY | | start_time | TIMESTAMP | | name | VARCHAR | |-------------+-------------| spectra table | column name | type | |----------------+-------------| | id | PRIMARY KEY | | name | VARCHAR | | index | INT | | spectrum_type | INT | | representation | INT | | run_id | FOREIGN KEY | |----------------+-------------| datapoints table | column name | type | |-------------+-------------| | id | PRIMARY KEY | | spectrum_id | FOREIGN KEY | | mz | DOUBLE | | num_counts | DOUBLE | | index | INT | |-------------+-------------| Is this reasonable?

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  • How can i get the seed value of an identity column in MySql

    - by mmcdonald
    To get the seed and step values of an identity column in sql server i can use this syntax SELECT ColumnName = name, Seed = seed_value, Step = increment_value FROM sys.identity_columns So far in MySql i have found that if i use this syntax SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE auto_increment IS NOT NULL I can at least find out which columns are an identity... The question being how can i get the SEED and STEP values of the identity column from the MySQL Schema.

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  • Getting ORACLE programming object definitions

    - by Yaakov Davis
    Let's say I have an ORACLE schema with contains a package. That package defines types, functions, procedures, etc: CREATE PACKAGE... DECLARE FUNCTION ... PROCEDURE ... END; Is there a query I can execute to get the definitions of those individual objects, without the wrapping package?

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  • Is it possible to write a database view that encompasses one-to-many relationships?

    - by Brandon Linton
    So I'm not necessarily saying this is even a good idea if it were possible, since the schema of the view would be extremely volatile, but is there any way to represent a has-many relationship in a single view? For example, let's say I have a customer that can have any number of addresses in the database. Is there any way to list out each column of each address with perhaps a number as a part of the alias (e.g., columns like Customer Id, Name, Address_Street_1, Address_Street_2, etc)? Thanks!

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  • Ruby-on-Rails equivalent to ORM Designer for Symfony?

    - by fayer
    In Symfony i just have to create models with ORM Designer and export it to symfony as a schema.yml and then use a symfony command to create tables, models and forms. I wonder if there is an equivalent to the RoR so that you dont have to create models manually by hand? It saves a lot of time using GUI for this kind of tasks and it is less error-prone. thanks

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  • diffing two databases

    - by flybywire
    Is there a tool to find the difference between two databases. Both the schema and the actual data are pretty much the same, but not 100%. Do you know a tool that can help to succinctly describe the changes.

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  • Max value amongst 4 columns in a row.

    - by KandadaBoggu
    I have test_scores table with following fields: Table schema: id (number) score1 (number) score2 (number) score3 (number) score4 (number) Sample data: id score1 score2 score3 score4 1 10 05 30 50 2 05 15 10 00 3 25 10 05 15 Expected result set: id col_name col_value 1 score4 50 2 score2 15 3 score1 25 What is a good SQL for this?(I am using MySQL.)

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  • How to build a tree from a list of items and their children recursively in php?

    - by k1lljoy
    I have a list of items stored in the DB, simplified schema is like this: id, parent, name I need to generate a tree structure (in a form of a multi-dimensional array) that can be infinite levels deep. Top level items would have parent = 0. Next level down would have parent equal to the the id of the parent item, fairly straight forward. What would be the best way to do this, while consuming as little resources as possible?

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  • SSIS Null Value Questions

    - by Saobi
    I have a table with 5 string columns, all can be NULLs. After I read the data from this table, I want to convert any null values into empty strings. The reason is that I need to compare these columns with columns in another table of the same schema (using conditional split), and null values would cause the comparison to evaluate to NULL. Is there any functionality in SSIS that allows me to convert NULL's to empty strings, or just not having to deal with NULL's at all?

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  • LINQ to SQL table naming

    - by Ivo
    I am using VS2010 and C# When I map/select my database tables with LINQ to SQL I have to option to change the "member" propery, but when i delete the table (because I changed something in the schema for example) and add it again the member value gets "reset". Is it possible to set/override this member programmaticly, so that I dont have to change it by hand everytime I mean the member option of '<'Table Name="dbo.table1" Member="table1"

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  • mysql circular dependency in foreign key constraints

    - by Flavius
    Given the schema: What I need is having every user_identities.belongs_to reference an users.id. At the same time, every users has a primary_identity as shown in the picture. However when I try to add this reference with ON DELETE NO ACTION ON UPDATE NO ACTION, MySQL says #1452 - Cannot add or update a child row: a foreign key constraint fails (yap.#sql-a3b_1bf, CONSTRAINT #sql-a3b_1bf_ibfk_1 FOREIGN KEY (belongs_to) REFERENCES users (id) ON DELETE NO ACTION ON UPDATE NO ACTION) I suspect this is due to the circular dependency, but how could I solve it (and maintain referential integrity)?

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  • Getting this error while reading excel from c#

    - by Lalit
    Hello all, I have code string conn = @"Provider=Microsoft.ACE.OLEDB.12.0;DSN=Excel Files;DBQ=" + strSheetPath + @";DriverId=1046;FIL=excel 12.0;MaxBufferSize=2048;PageTimeout=5;"; //string conn = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + strSheetPath +";Extended Properties=Excel 12.0 Xml;HDR=YES;IMEX=1"; string destinationConnectionString = ConfigurationManager.ConnectionStrings["KGD6DBConnectionString"].ConnectionString; string query = "Select * From [Sheet1$]"; using (var myConnection = new OleDbConnection(conn)) using (var destinationConnection = new SqlConnection(destinationConnectionString)) using (var bulkCopy = new SqlBulkCopy(destinationConnection)) { //Map first column in source to second column in sql table (skipping the ID column). //Excel schema[CompanyName,Phone] Table schema[ShipperID, CompanyName, Phone] bulkCopy.ColumnMappings.Add(0, 1); bulkCopy.ColumnMappings.Add(1, 2); bulkCopy.ColumnMappings.Add(2, 3); bulkCopy.ColumnMappings.Add(3, 4); bulkCopy.ColumnMappings.Add(4, 5); bulkCopy.ColumnMappings.Add(5, 6); bulkCopy.ColumnMappings.Add(6, 7); bulkCopy.ColumnMappings.Add(7, 8); bulkCopy.ColumnMappings.Add(8, 9); bulkCopy.ColumnMappings.Add(9, 10); bulkCopy.ColumnMappings.Add(10, 11); bulkCopy.ColumnMappings.Add(11, 12); bulkCopy.ColumnMappings.Add(12, 13); bulkCopy.ColumnMappings.Add(13, 14); bulkCopy.ColumnMappings.Add(14, 15); bulkCopy.ColumnMappings.Add(15, 16); bulkCopy.ColumnMappings.Add(16, 17); bulkCopy.ColumnMappings.Add(17, 18); bulkCopy.ColumnMappings.Add(18, 19); bulkCopy.ColumnMappings.Add(19, 20); bulkCopy.ColumnMappings.Add(20, 21); bulkCopy.ColumnMappings.Add(21, 22); bulkCopy.ColumnMappings.Add(22, 23); bulkCopy.ColumnMappings.Add(23, 24); bulkCopy.DestinationTableName = "dbo.sampleInventory"; using (var myCommand = new OleDbCommand(query, myConnection)) { myConnection.Open(); destinationConnection.Open(); var myReader = myCommand.ExecuteReader(); while (myReader.Read()) { bulkCopy.WriteToServer(myReader); } } } return (new DataTable()); getting error on connection opening line. Error: Could not find installable ISAM.

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  • Whats the best way to design this database scenario?

    - by ankimal
    I want to setup 2 MySQL databases which differ in schema in that, one is normalized and the other is flat for quicker reads and writes. The information being stored in both DBs is the same, but the representation is obviously different owing to the different design approaches. I need to find a robust solution to sync information in real time from my normalized version to my flatter version.

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  • Transforming OLTP Relational Database to Data Warehousing Model

    - by Russ Cam
    What are the common design approaches taken in loading data from a typical Entity-Relationship OLTP database model into a Kimball star schema Data Warehouse/Marts model? Do you use a staging area to perform the transformation and then load into the warehouse? How do you link data between the warehouse and the OLTP database? Where/How do you manage the transformation process - in the database as sprocs, dts/ssis packages, or SQL from application code?

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  • How can I build a voting system to support multiple types of objects to vote on?

    - by Kyle Hayes
    I'm really looking for something very similar to the way SO is setup where a few different kinds of things can be voted on (questions AND answers). What kind of DB schema, generally, could I use to support voting on many different kinds of objects? Would I have a single Vote table that would have references to other objects in the database? Or do I have to have or should have a separate vote table for each of the objects I would like to vote on.

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  • Different information domains in DB

    - by dotnetdev
    Hi, I have a database for my personal site and at the moment it is storing different domains of information (Eg cv, CMS schema, and more, all in one DB). I have noticed that sets of tables (eg all for one domain) have no relationship to other groups of tables as they are completely unrelated. What implication does this have on database design? I can assume this is a time I need to think about having 1 DB.

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  • Getting this error while reading excel

    - by Lalit
    I have code string conn = @"Provider=Microsoft.ACE.OLEDB.12.0;DSN=Excel Files;DBQ=" + strSheetPath + @";DriverId=1046;FIL=excel 12.0;MaxBufferSize=2048;PageTimeout=5;"; //string conn = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + strSheetPath +";Extended Properties=Excel 12.0 Xml;HDR=YES;IMEX=1"; string destinationConnectionString = ConfigurationManager.ConnectionStrings["KGD6DBConnectionString"].ConnectionString; string query = "Select * From [Sheet1$]"; using (var myConnection = new OleDbConnection(conn)) using (var destinationConnection = new SqlConnection(destinationConnectionString)) using (var bulkCopy = new SqlBulkCopy(destinationConnection)) { //Map first column in source to second column in sql table (skipping the ID column). //Excel schema[CompanyName,Phone] Table schema[ShipperID, CompanyName, Phone] bulkCopy.ColumnMappings.Add(0, 1); bulkCopy.ColumnMappings.Add(1, 2); bulkCopy.ColumnMappings.Add(2, 3); bulkCopy.ColumnMappings.Add(3, 4); bulkCopy.ColumnMappings.Add(4, 5); bulkCopy.ColumnMappings.Add(5, 6); bulkCopy.ColumnMappings.Add(6, 7); bulkCopy.ColumnMappings.Add(7, 8); bulkCopy.ColumnMappings.Add(8, 9); bulkCopy.ColumnMappings.Add(9, 10); bulkCopy.ColumnMappings.Add(10, 11); bulkCopy.ColumnMappings.Add(11, 12); bulkCopy.ColumnMappings.Add(12, 13); bulkCopy.ColumnMappings.Add(13, 14); bulkCopy.ColumnMappings.Add(14, 15); bulkCopy.ColumnMappings.Add(15, 16); bulkCopy.ColumnMappings.Add(16, 17); bulkCopy.ColumnMappings.Add(17, 18); bulkCopy.ColumnMappings.Add(18, 19); bulkCopy.ColumnMappings.Add(19, 20); bulkCopy.ColumnMappings.Add(20, 21); bulkCopy.ColumnMappings.Add(21, 22); bulkCopy.ColumnMappings.Add(22, 23); bulkCopy.ColumnMappings.Add(23, 24); bulkCopy.DestinationTableName = "dbo.sampleInventory"; using (var myCommand = new OleDbCommand(query, myConnection)) { myConnection.Open(); destinationConnection.Open(); var myReader = myCommand.ExecuteReader(); while (myReader.Read()) { bulkCopy.WriteToServer(myReader); } } } return (new DataTable()); getting error on connection opening line. Error: Could not find installable ISAM.

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