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  • Modeling a Generic Relationship in a Database

    - by StevenH
    This is most likely one for all you sexy DBAs out there: How would I effieciently model a relational database whereby I have a field in an "Event" table which defines a "SportType". This "SportsType" field can hold a link to different sports tables E.g. "FootballEvent", "RubgyEvent", "CricketEvent" and "F1 Event". Each of these Sports tables have different fields specific to that sport. My goal is to be able to genericly add sports types in the future as required, yet hold sport specific event data (fields) as part of my Event Entity. Is it possible to use an ORM such as NHibernate / Entity framework which would reflect such a relationship? I have thrown together a quick C# example to express my intent at a higher level: public class Event<T> where T : new() { public T Fields { get; set; } public Event() { EventType = new T(); } } public class FootballEvent { public Team CompetitorA { get; set; } public Team CompetitorB { get; set; } } public class TennisEvent { public Player CompetitorA { get; set; } public Player CompetitorB { get; set; } } public class F1RacingEvent { public List<Player> Drivers { get; set; } public List<Team> Teams { get; set; } } public class Team { public IEnumerable<Player> Squad { get; set; } } public class Player { public string Name { get; set; } public DateTime DOB { get; set;} }

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  • Modeling a Generic Relationship (expressed in C#) in a Database

    - by StevenH
    This is most likely one for all you sexy DBAs out there: How would I effieciently model a relational database whereby I have a field in an "Event" table which defines a "SportType"? This "SportsType" field can hold a link to different sports tables E.g. "FootballEvent", "RubgyEvent", "CricketEvent" and "F1 Event". Each of these Sports tables have different fields specific to that sport. My goal is to be able to genericly add sports types in the future as required, yet hold sport specific event data (fields) as part of my Event Entity. Is it possible to use an ORM such as NHibernate / Entity framework / DataObjects.NET which would reflect such a relationship? I have thrown together a quick C# example to express my intent at a higher level: public class Event<T> where T : new() { public T Fields { get; set; } public Event() { EventType = new T(); } } public class FootballEvent { public Team CompetitorA { get; set; } public Team CompetitorB { get; set; } } public class TennisEvent { public Player CompetitorA { get; set; } public Player CompetitorB { get; set; } } public class F1RacingEvent { public List<Player> Drivers { get; set; } public List<Team> Teams { get; set; } } public class Team { public IEnumerable<Player> Squad { get; set; } } public class Player { public string Name { get; set; } public DateTime DOB { get; set;} }

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  • Design pattern for logging changes in parent/child objects saved to database

    - by andrew
    I’ve got a 2 database tables in parent/child relationship as one-many. I’ve got three classes representing the data in these two tables: Parent Class { Public int ID {get; set;} .. other properties } Child Class { Public int ID {get;set;} Public int ParentID {get; set;} .. other properties } TogetherClass { Public Parent Parent; Public List<Child> ChildList; } Lastly I’ve got a client and server application – I’m in control of both ends so can make changes to both programs as I need to. Client makes a request for ParentID and receives a Together Class for the matching parent, and all of the child records. The client app may make changes to the children – add new children, remove or modify existing ones. Client app then sends the Together Class back to the server app. Server app needs to update the parent and child records in the database. In addition I would like to be able to log the changes – I’m doing this by having 2 separate tables one for Parent, one for child; each containing the same columns as the original plus date time modified, by whom and a list of the changes. I’m unsure as to the best approach to detect the changes in records – new records, records to be deleted, records with no fields changed, records with some fields changed. I figure I need to read the parent & children records and compare those to the ones in the Together Class. Strategy A: If Together class’s child record has an ID of say 0, that indicates a new record; insert. Any deleted child records are no longer in the Together Class; see if any of the comparison child records are not found in the Together class and delete if not found (Compare using ID). Check each child record for changes and if changed log. Strategy B: Make a new Updated TogetherClass UpdatedClass { Public Parent Parent {get; set} Public List<Child> ListNewChild {get;set;} Public List<Child> DeletedChild {get;set;} Public List<Child> ExistingChild {get;set;} // used for no changes and modified rows } And then process as per the list. The reason why I’m asking for ideas is that both of these solutions don’t seem optimal to me and I suspect this problem has been solved already – some kind of design pattern ? I am aware of one potential problem in this general approach – that where Client App A requests a record; App B requests same record; A then saves changes; B then saves changes which may overwrite changes A made. This is a separate locking issue which I’ll raise a separate question for if I’ve got trouble implementing. The actual implementation is c#, SQL Server and WCF between client and server - sharing a library containing the class implementations. Apologies if this is a duplicate post – I tried searching various terms without finding a match though.

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  • Which Table Should be Master and Child in Database Design

    - by Jason
    I am quickly learning the ins and outs of database design (something that, as of a week ago, was new to me), but I am running across some questions that don't seem immediately obvious, so I was hoping to get some clarification. The question I have right is about foreign keys. As part of my design, I have a Company table. Originally, I had included address information directly within the table, but, as I was hoping to achieve 3NF, I broke out the address information into its own table, Address. In order to maintain data integrity, I created a row in Company called "addressId" as an INT and the Address table has a corresponding addressId as its primary key. What I'm a little bit confused about (or what I want to make sure I'm doing correctly) is determining which table should be the master (referenced) table and which should be the child (referencing) table. When I originally set this up, I made the Address table the master and the Company the child. However, I now believe this is wrong due to the fact that there should be only one address per Company and, if a Company row is deleted, I would want the corresponding Address to be removed as well (CASCADE deletion). I may be approaching this completely wrong, so I would appreciate any good rules of thumb on how to best think about the relationship between tables when using foreign keys. Thanks!

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  • Postgre database ignoring created index ?!

    - by drasto
    I have an Postgre database and a table called my_table. There are 4 columns in that table (id, column1, column2, column3). The id column is primary key, there are no other constrains or indexes on columns. The table has about 200000 rows. I want to print out all rows which has value of column column2 equal(case insensitive) to 'value12'. I use this: SELECT * FROM my_table WHERE column2 = lower('value12') here is the execution plan for this statement(result of set enable_seqscan=on; EXPLAIN SELECT * FROM my_table WHERE column2 = lower('value12')): Seq Scan on my_table (cost=0.00..4676.00 rows=10000 width=55) Filter: ((column2)::text = 'value12'::text) I consider this to be to slow so I create an index on column column2 for better prerformance of searches: CREATE INDEX my_index ON my_table (lower(column2)) Now I ran the same select: SELECT * FROM my_table WHERE column2 = lower('value12') and I expect it to be much faster because it can use index. However it is not faster, it is as slow as before. So I check the execution plan and it is the same as before(see above). So it still uses sequential scen and it ignores the index! Where is the problem ?

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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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  • Should we denormalize database to improve performance?

    - by Groo
    We have a requirement to store 500 measurements per second, coming from several devices. Each measurement consists of a timestamp, a quantity type, and several vector values. Right now there is 8 vector values per measurement, and we may consider this number to be constant for needs of our prototype project. We are using HNibernate. Tests are done in SQLite (disk file db, not in-memory), but production will probably be MsSQL. Our Measurement entity class is the one that holds a single measurement, and looks like this: public class Measurement { public virtual Guid Id { get; private set; } public virtual Device Device { get; private set; } public virtual Timestamp Timestamp { get; private set; } public virtual IList<VectorValue> Vectors { get; private set; } } Vector values are stored in a separate table, so that each of them references its parent measurement through a foreign key. We have done a couple of things to ensure that generated SQL is (reasonably) efficient: we are using Guid.Comb for generating IDs, we are flushing around 500 items in a single transaction, ADO.Net batch size is set to 100 (I think SQLIte does not support batch updates? But it might be useful later). The problem Right now we can insert 150-200 measurements per second (which is not fast enough, although this is SQLite we are talking about). Looking at the generated SQL, we can see that in a single transaction we insert (as expected): 1 timestamp 1 measurement 8 vector values which means that we are actually doing 10x more single table inserts: 1500-2000 per second. If we placed everything (all 8 vector values and the timestamp) into the measurement table (adding 9 dedicated columns), it seems that we could increase our insert speed up to 10 times. Switching to SQL server will improve performance, but we would like to know if there might be a way to avoid unnecessary performance costs related to the way database is organized right now. [Edit] With in-memory SQLite I get around 350 items/sec (3500 single table inserts), which I believe is about as good as it gets with NHibernate (taking this post for reference: http://ayende.com/Blog/archive/2009/08/22/nhibernate-perf-tricks.aspx). But I might as well switch to SQL server and stop assuming things, right? I will update my post as soon as I test it.

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  • SQL In The City Charlotte - Fundamentals of Database Design

    - by drsql
    Next Monday, October 14, at Red-Gate's SQL In The City conference in Charlotte, NC (one day before PASS), I will be presenting my Fundamentals of Database Design session. It is my big-time chestnut session, the one that I do the most and have the most fun with. This will be the "single" version of the session, weighing in at just under an hour, and it is a lot of material to go over (even with no code samples to go awry to take up time.)  In this hour long session (presented in widescreen...(read more)

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  • choosing Database and Its Design for Rails

    - by Gaurav Shah
    I am having a difficulty in deciding the database & its structure. Let us say the problem is like this. For my product I have various customers( each is an educational institute) Each customer have their own sub-clients ( Institution have students) Each student record will have some basic information like "name" & "Number" . There are also additional information that a customer(institution) might want to ask sub-client(student) like "email" or "semester" I have come up with two solutions : 1. Mysql _insititution__ id-|- Description| __Student__ id-|-instituition_id-|-Name-|-Number| __student_additional_details__ student_id -|- field_name -|- Value Student_additional_details will have multiple records for each student depending upon number of questions asked from institution. 2.MongoDb _insititution___ id-|- Description| _Student__ id-|-instituition_id-|-Name-|-Number|-otherfield1 -|- otherfield2 with mongo the structure itself can be dynamic so student table seems really good in mongo . But the problem comes when I have to relate student with institution . So which one is a better design ? Or some other idea ?

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  • TDE Tablespace Encryption 11.2.0.1 Certified with EBS 11i

    - by Steven Chan
    Oracle Advanced Security is an optional licenced Oracle 11g Database add-on.  Oracle Advanced Security Transparent Data Encryption (TDE) offers two different features:  column encryption and tablespace encryption.  TDE Tablespace Encryption 11.2.0.1 is now certified with Oracle E-Business Suite Release 11i. What is Transparent Data Encryption (TDE) ? Oracle Advanced Security Transparent Data Encryption (TDE) allows you to protect data at rest. TDE helps address privacy and PCI requirements by encrypting personally identifiable information (PII) such as Social Security numbers and credit card numbers. TDE is completely transparent to existing applications with no triggers, views or other application changes required. Data is transparently encrypted when written to disk and transparently decrypted after an application user has successfully authenticated and passed all authorization checks. Authorization checks include verifying the user has the necessary select and update privileges on the application table and checking Database Vault, Label Security and Virtual Private Database enforcement policies.

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  • Database vs Networking

    - by user16258
    I have completed my diploma in (IT) and now pursuing degree, i am in last semester of my B.E(I.T). I want to do specialization either in Database(oracle) or in Networking(cisco). Which one of two will be in more demand in near future, i know it's all about interest but still i would like to know your opinion. Most of people say that a network engineer is never paid as better as a programmer or a DBA, and few says they do get paid well. What would be the scope if i clear my CCNA and CCNP exams, or either OCA & OCP exams, what would be more rewarding. Also i have read somewhere that most of the task of DBA will be automated so in future demand of a DBA will reduce. I would also like to hear from Network engineers what's the scenario out there in India. Thanks

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  • Performing a clean database creation using msbuild

    - by Robert May
    So I’m taking a break from writing about other Agile stuff for a post. :)  I’m still going to get back to the other subjects, but this is fun too. Something I’ve done quite a bit of is MSBuild and CI work.  I’m experimenting with ways to improve what I’ve done in the past, particularly around database CI. Today, I developed a mechanism for starting from scratch with your database.  By scratch, I mean blowing away the existing database and creating it again from a single command line call.  I’m a firm believer that developers should be able to get to a known clean state at the database level with a single command and that they should be operating off of their own isolated database to improve productivity.  These scripts will help that. Here’s how I did it.  First, we have to disconnect users.  I did so using the help of a script from sql server central.  Note that I’m using sqlcmd variable replacement. -- kills all the users in a particular database -- dlhatheway/3M, 11-Jun-2000 declare @arg_dbname sysname declare @a_spid smallint declare @msg varchar(255) declare @a_dbid int set @arg_dbname = '$(DatabaseName)' select @a_dbid = sdb.dbid from master..sysdatabases sdb where sdb.name = @arg_dbname declare db_users insensitive cursor for select sp.spid from master..sysprocesses sp where sp.dbid = @a_dbid open db_users fetch next from db_users into @a_spid while @@fetch_status = 0 begin select @msg = 'kill '+convert(char(5),@a_spid) print @msg execute (@msg) fetch next from db_users into @a_spid end close db_users deallocate db_users GO Once all users are booted from the database, we can commence with recreating the database.  I generated the script that is used to create a database from SQL Server management studio, so I’m only going to show the bits that weren’t generated that are important.  There are a bunch of Alter Database statements that aren’t shown. First, I had to find the default location of the database files in the install, since they can be in many different locations.  I used Method 1 from a technet blog and then modified it a bit to do what I needed to do.  I ended up using dynamic SQL because for the life of me, I couldn’t get the “Filename” property to not return an error when I used anything besides a string.  I’m dropping the database first, if it exists.  Here’s the code:   IF EXISTS(SELECT 1 FROM [master].[sys].[databases] WHERE [name] = N'$(DatabaseName)') BEGIN drop database $(DatabaseName) END; go IF EXISTS(SELECT 1 FROM [master].[sys].[databases] WHERE [name] = 'zzTempDBForDefaultPath') BEGIN DROP DATABASE zzTempDBForDefaultPath END; -- Create temp database. Because no options are given, the default data and --- log path locations are used CREATE DATABASE zzTempDBForDefaultPath; DECLARE @Default_Data_Path VARCHAR(512), @Default_Log_Path VARCHAR(512); --Get the default data path SELECT @Default_Data_Path = ( SELECT LEFT(physical_name,LEN(physical_name)-CHARINDEX('\',REVERSE(physical_name))+1) FROM sys.master_files mf INNER JOIN sys.[databases] d ON mf.[database_id] = d.[database_id] WHERE d.[name] = 'zzTempDBForDefaultPath' AND type = 0); --Get the default Log path SELECT @Default_Log_Path = ( SELECT LEFT(physical_name,LEN(physical_name)-CHARINDEX('\',REVERSE(physical_name))+1) FROM sys.master_files mf INNER JOIN sys.[databases] d ON mf.[database_id] = d.[database_id] WHERE d.[name] = 'zzTempDBForDefaultPath' AND type = 1); --Clean up. IF EXISTS(SELECT 1 FROM [master].[sys].[databases] WHERE [name] = 'zzTempDBForDefaultPath') BEGIN DROP DATABASE zzTempDBForDefaultPath END; DECLARE @SQL nvarchar(max) SET @SQL= 'CREATE DATABASE $(DatabaseName) ON PRIMARY ( NAME = N''$(DatabaseName)'', FILENAME = N''' + @Default_Data_Path + N'$(DatabaseName)' + '.mdf' + ''', SIZE = 2048KB , FILEGROWTH = 1024KB ) LOG ON ( NAME = N''$(DatabaseName)Log'', FILENAME = N''' + @Default_Log_Path + N'$(DatabaseName)' + '.ldf' + ''', SIZE = 1024KB , FILEGROWTH = 10%) ' exec (@SQL) GO And with that, your database is created.  You can run these scripts on any server and on any database name.  To do that, I created an MSBuild script that looks like this: <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0"> <PropertyGroup> <DatabaseName>MyDatabase</DatabaseName> <Server>localhost</Server> <SqlCmd>sqlcmd -v DatabaseName=$(DatabaseName) -S $(Server) -i </SqlCmd> <ScriptDirectory>.\Scripts</ScriptDirectory> </PropertyGroup> <Target Name ="Rebuild"> <ItemGroup> <ScriptFiles Include="$(ScriptDirectory)\*.sql"/> </ItemGroup> <Exec Command="$(SqlCmd) &quot;%(ScriptFiles.Identity)&quot;" ContinueOnError="false"/> </Target> </Project> Note that the Scripts directory is underneath the directory where I’m running the msbuild command and is relative to that directory.  Note also that the target is using batching to run each script in the scripts subdirectory, one after the other.  Each script is passed to the sqlcmd command line execution using the .Identity property on the itemgroup that is created.  This target file is saved in the file “Database.target”. To make this work, you’ll need msbuild in your path, and then run the following command: msbuild database.target /target:Rebuild Once you’ve got your virgin database setup, you’d then need to use a tool like dbdeploy.net to determine that it was a virgin database, build a change script based on the change scripts, and then you’d want another sqlcmd call to update the database with the appropriate scripts.  I’m doing that next, so I’ll post a blog update when I’ve got it working. Technorati Tags: MSBuild,Agile,CI,Database

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  • Designing persistence schema for BigTable on AppEngine

    - by Vitalij Zadneprovskij
    I have tried to design the datastore schema for a very small application. That schema would have been very simple, if not trivial, using a relational database with foreign keys, many-to-many relations, joins, etc. But the problem was that my application was targeted for Google App Engine and I had to design for a database that was not relational. At the end I gave up. Is there a book or an article that describes design principles for applications that are meant for such databases? The books that I have found are about programming for App Engine and they don't spend many words about database design principles.

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  • Oracle Database Machine: customer case at OOW2010

    - by rene.kundersma
    I proudly announce that on Openworld 2010, together with TUI I will be co-presenting the customer case on their Database Machine implementation. Our session number is S314935. The sesison will be about the business case, the choices made for the setup, how we did the migration to v1, the migration to v2. Also how we implemented backup/restore and disaster recovery solutions. It will be a very interesting case for everyone interested in customer implementations of the DBM ! Hope to see you there Rene Kundersma Technical Architect Oracle Technology Services

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  • Using SMO to drop a SQL Database

    - by ybbest
    SQL Server Management Objects(SMO) is the API you can use to manipulate the sql server,like create databse and delete database. To get more details you can check the msdn documentation. There are 2 ways you can drop a database 1. You could create a Database object and call Drop method: Dim database As Database = New Database(Your database name) database.Drop() 2.However if you have existing connections to the database ,attempting to drop it using the above method will fail.Recall that when you try to drop the database from management studio ,you can tick the check box to close all the connections before drop the database.It is not so obvious , but you can do the exact same thing using SMO: Dim server As Server= New Server(ServerConn) server.KillAllProcesses(Your database name) server.KillDatabase(Your database name)

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  • Best approach to accessing multiple data source in a web application

    - by ced
    I've a base web application developed with .net technologies (asp.net) used into our LAN by 30 users simultanousley. From this web application I've developed two verticalization used from online users. In future i expect hundreds users simultanousley. Our company has different locations. Each site use its own database. The web application needs to retrieve information from all existing databases. Currently there are 3 database, but it's not excluded in the future expansion of new offices. My question then is: What is the best strategy for a web application to retrieve information from different databases (which have the same schema) whereas the main objective performance data access and high fault tolerance? There are case studies in the literature that I can take as an example? Do you know some good documents to study? Do you have any tips to implement this task so efficient? Intuitively I would say that two possible strategy are: perform queries from different sources in real time and aggregate data on the fly; create a repository that contains the union of the entities of interest and perform queries directly on repository;

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  • Database IDs

    - by fatherjack
    Just a quick post, mainly to test out the new blog format but related to a question on the #sqlhelp hashtag. The question came from Justin Dearing (@zippy1981) as: So I take it database_id isn’t an ever incrementing value. #sqlhelp When a new database is created it is given the lowest available ID. This either is in a gap in IDs where a database has been dropped or the database ID is incremented by one from the highest current ID if there are no gaps to fill. To see this in action, connect to your sandbox server and try this: USE MASTER GO CREATE DATABASE cherry GO USE cherry GO SELECT DB_ID() GO CREATE DATABASE grape GO USE grape GO SELECT DB_ID() GO CREATE DATABASE melon GO USE melon GO SELECT DB_ID() GO USE MASTER GO DROP DATABASE grape GO CREATE DATABASE kiwi GO USE kiwi GO SELECT DB_ID() GO USE MASTER GO DROP DATABASE cherry DROP DATABASE melon DROP DATABASE kiwi You should get an incrementing series of database IDs as the databases are created until the last one where the new database gets allocated the ID that is missing because one was dropped.

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  • Do database tables need to have IDs?

    - by Arturas M
    Is an ID field is always needed in database tables? In my case I have a user with firstName, lastName and email fields. email is unique and not null, so it could be used as an ID, right? So in that case, could/should I try to remove the ID? Also I want to have another table which extends this one. Let's say its called patient and it has it's own field additionalData and I would like to link the relationship through the email of user I mentioned. So the relationship should be 1 to 1, right? and I wouldn't need the IDs? Somehow MySQL Workbench wants me to use the IDs. What do you guys think. Any suggestions on this topic?

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  • Login - check database if user exists... (c#)

    - by SAMIR BHOGAYTA
    I have managed to do the following... string connectionString = "datasource=localhost;username=xxx;password=xxx;database=xxx"; MySqlConnection mySqlConnection = new MySqlConnection(connectionString); string selectString = "SELECT username, password " + "FROM forum_members " + "WHERE username = '" + frmUsername.Text + "' AND password = '" + frmPassword.Text + "'"; MySqlCommand mySqlCommand = new MySqlCommand(selectString, mySqlConnection); mySqlConnection.Open(); String strResult = String.Empty; strResult = (String)mySqlCommand.ExecuteScalar(); mySqlConnection.Close(); if (strResult.Length == 0) { Label1.Text = "INCORRECT USER/PASS!" //could redirect to register page } else { Label1.Text = "YOU ARE LOGGED IN!"; //set loggin in sessions variables }

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  • .mdf Database Filetype

    - by James Izzard
    Would somebody be kind enough to correct my understanding of the following (if incorrect)? Microsoft's .mdf file-type can be used by both the LocalDB and the full Server database engines (apologies if engine is not the correct word?). The .mdf file does not care which of these two options are accessing it - so you could use either to access any given .mdf file, provided you had permissions and password etc. The LocalDB and the SQL Server are two options that can be interchangeably chosen to access .mdf files depending on the application requirements. Appreciate any clarification. Thanks

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  • Webhosting with custom database choice [closed]

    - by churchill614
    Possible Duplicate: How to find web hosting that meets my requirements? I am trying to find somewhere to host a website which uses OrientDB as its database. My budget doesn't stretch to a dedicated server where I can configure everything as I need it. Rather, I am hoping to find somewhere, ideally UK based, that will allow me to install/install for me OrientDB on their server, that is of the normal shared server variety. Is anybody able to point me in a good direction for this please (whilst UK is preferable it is not essential)?

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  • DB Schema for ACL involving 3 subdomains

    - by blacktie24
    Hi, I am trying to design a database schema for a web app which has 3 subdomains: a) internal employees b) clients c) contractors. The users will be able to communicate with each other to some degree, and there may be some resources that overlap between them. Any thoughts about this schema? Really appreciate your time and thoughts on this. Cheers! -- -- Table structure for table locations CREATE TABLE IF NOT EXISTS locations ( id bigint(20) NOT NULL, name varchar(250) NOT NULL ) ENGINE=InnoDB DEFAULT CHARSET=latin1; -- -- Table structure for table privileges CREATE TABLE IF NOT EXISTS privileges ( id int(11) NOT NULL AUTO_INCREMENT, name varchar(255) NOT NULL, resource_id int(11) NOT NULL, PRIMARY KEY (id) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=10 ; -- -- Table structure for table resources CREATE TABLE IF NOT EXISTS resources ( id int(11) NOT NULL AUTO_INCREMENT, name varchar(255) NOT NULL, user_type enum('internal','client','expert') NOT NULL, PRIMARY KEY (id) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=3 ; -- -- Table structure for table roles CREATE TABLE IF NOT EXISTS roles ( id int(11) NOT NULL AUTO_INCREMENT, name varchar(255) NOT NULL, type enum('position','department') NOT NULL, parent_id int(11) DEFAULT NULL, user_type enum('internal','client','expert') NOT NULL, PRIMARY KEY (id) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=3 ; -- -- Table structure for table role_perms CREATE TABLE IF NOT EXISTS role_perms ( id int(11) NOT NULL AUTO_INCREMENT, role_id int(11) NOT NULL, privilege_id int(11) NOT NULL, mode varchar(250) NOT NULL, PRIMARY KEY (id) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=2 ; -- -- Table structure for table users CREATE TABLE IF NOT EXISTS users ( id int(10) unsigned NOT NULL AUTO_INCREMENT, email varchar(255) NOT NULL, password varchar(255) NOT NULL, salt varchar(255) NOT NULL, type enum('internal','client','expert') NOT NULL, first_name varchar(255) NOT NULL, last_name varchar(255) NOT NULL, location_id int(11) NOT NULL, phone varchar(255) NOT NULL, status enum('active','inactive') NOT NULL DEFAULT 'active', PRIMARY KEY (id) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=4 ; -- -- Table structure for table user_perms CREATE TABLE IF NOT EXISTS user_perms ( id int(11) NOT NULL AUTO_INCREMENT, user_id int(11) NOT NULL, privilege_id int(11) NOT NULL, mode varchar(250) NOT NULL, PRIMARY KEY (id) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=2 ; -- -- Table structure for table user_roles CREATE TABLE IF NOT EXISTS user_roles ( id int(11) NOT NULL, user_id int(11) NOT NULL, role_id int(11) NOT NULL ) ENGINE=InnoDB DEFAULT CHARSET=latin1;

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  • I need an approach to the problem of preventing inserting duplicate records into the database

    - by Maurice
    Apologies is this question is asked on the incorrect "stack" A webservice that I call returns a list of data. The data from the webservice is updated periodically, so a call to the webservice done in one hour could return the same data as a call done in an hour. Also, the data is returned based on a start and end date. We have multiple users that can run the webservice search, and duplicate data is most likely to be returned (especially for historical data). However I don't want to insert this duplicate data in the database. I've created a db table in which the data is stored (most important columns are) Id int autoincrement PK Date date not null --The date to which the data set belongs. LastUpdate date not null --The date the data set was last updated. UserName varchar(50) --The name of the user doing the search. I use sql server 2008 express with c# 4.0 and visual studio 2010. Entity Framework is used as the ORM. If stored procedures could be avoided in the proposed solution, then that will be a plus. Another way of looking interpreting what I'm asking a solution for is as follows: I have a million unique records in my table. A user does a new search. The search results from the user contains around 300k of the data that is already in the db. An efficient solution to finding an inserting only the unique records is needed.

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  • How to define a natural id in database?

    - by gcc
    There are a lot of manuals. I am trying to create an database to hold information of these documents. But, there is a small problem. How can I give meaningful id to the manuals? Are there any standard or logic behind the giving meaningful id to the documents? If there is no standard, can you tell me how I should do that? example: table : manual id | manual name EDIT: Not Meaningful ID 1 or M1 or foo 2 C2 bar 3 P123 name ... ... ... (i) (ii) (iii) (i) Not meaningful for me because if some item deleted, there can be gap. ex 1 33 100. (ii) random character can be confusing when one try to give a name to new manual (iii) Why giving name is not preferred is because finding a name to the manual as ID is hard after 500 manuals. Meaningful : New ID * Can be easily produced even if after 1000 manuals * Should not be so complicated

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  • how to give meaningful id to the things in database

    - by gcc
    There are a lot of manuals. I am trying to create an database to hold information of these documents. But, there is a small problem. How can I give meaningful id to the manuals? Are there any standard or logic behind the giving meaningful id to the documents? If there is no standard, can you tell me how I should do that? example: table : manual id | manual name EDIT: Not Meaningful ID 1 or M1 or foo 2 C2 bar 3 P123 name ... ... ... (i) (ii) (iii) (i) Not meaningful for me because if some item deleted, there can be gap. ex 1 33 100. (ii) random character can be confusing when one try to give a name to new manual (iii) Why giving name is not preferred is because finding a name to the manual as ID is hard after 500 manuals. Meaningful : New ID * Can be easily produced even if after 1000 manuals * Should not be so complicated

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