I'm trying to use entity framework with an adapter structure, my goal will be to have a single .edmx structure able to manage several connections.
I need to have those adapters:
file based database (SqlServerCE 3.5)
MySql (with its custom provider from Oracle)
Oracle (as MySql)
SqlServer
I have a DAO class that receives a bean (dependency injection object) with data connection from a winform, than due to a specific info in that bean, the DAO will load the correct adapter, through a Database factory class.
My Database factory will load a real adaptor class (e.g. for mysql A_Mysql.cs that implement my abstract adapter class).
In particular, I would like to understand hop I can modify in the adaptor the connection method:
public override Entities createConnection(DbConnection dbBean)
{
string conn =
#"metadata=res://*/Toolkit.Database.External.ADO.ADODatabase.csdl" +
#"|res://*/Toolkit.Database.External.ADO.ADODatabase.ssdl" +
#"|res://*/Toolkit.Database.External.ADO.ADODatabase.msl;" +
#"provider=MySql.Data.MySqlClient;" +
"provider connection string=\"Persist Security Info=True;server=" + dbBean.Server + ";" +
"Port=" + dbBean.Port + ";" +
"User Id=" + dbBean.Username + ";"+
"Password=" + dbBean.Password + ";" +
"database=" + dbBean.Schema + "\"";
Entities entities = new Entities(conn);
return entities;
}
to use the same .edmx, in my DAO…
I was pretty sure that this was the right way, unfortunately this system is always returning me errors from SqlCE (I have generated the first .emdx from SqlServerCE, but it does not contain any informations about that database and my App.config file has NOT stored database informations)…
Can you help me? Please write me back for further information, if needed.
Thank you.
Your data access layer will need to be abstracted at the entity provider level, not the database connection level. You're basically talking about using the repository pattern. You will need to have a separate context for each provider you plan to support, because that's ultimately what's responsible for translating your Linq queries into the correct SQL syntax for a specific database platform. Each context should implement the same interface (which is your repository interface). In your code, you do everything against that interface, not the actual context types. Then use a Dependency Injection framework (such as Ninject) to manage instantiating the correct context implementation for the database provider you're using.
It will not work because EDMX itself contains information about database provider. Also whole database description stored in EDMX targets single database provider. There is even difference between SQL Server 2005 and 2008. You need at least separate SSDL part for every database you want to support.
I've a post on mi site on how to use multiple connection to multiple databases [it's in spanish :)]
Post
Regards.
Related
I am developping J2EE application with appfuse that have default settings with mySQL
<!-- Database settings -->
<dbunit.dataTypeFactoryName>org.dbunit.ext.mysql.MySqlDataTypeFactory</dbunit.dataTypeFactoryName>
<dbunit.operation.type>CLEAN_INSERT</dbunit.operation.type>
<hibernate.dialect>org.hibernate.dialect.MySQL5InnoDBDialect</hibernate.dialect>
<jdbc.groupId>mysql</jdbc.groupId>
<jdbc.artifactId>mysql-connector-java</jdbc.artifactId>
<jdbc.version>5.1.27</jdbc.version>
<jdbc.driverClassName>com.mysql.jdbc.Driver</jdbc.driverClassName>
<jdbc.url>jdbc:mysql://localhost/${db.name}?createDatabaseIfNotExist=true&useUnicode=true&characterEncoding=utf-8&autoReconnect=true</jdbc.url>
<jdbc.username>root</jdbc.username>
<jdbc.password></jdbc.password>
<jdbc.validationQuery>SELECT 1 + 1</jdbc.validationQuery>
But i need to connect my application with external database (SQL QERVER)to retreive some data.
I need help to configure maven to use two different database (mysql +sql server)
maven will help you out with loading of the driver jar files. You would be creating two data source / session factory to achieve this.
I think this can be achieved quite easily in a brief guideline as follows:
Create a second "dataSource" bean definition in applicationContext-resources.xml with MSSQL specific values such as driver class, url etc. Give it a different bean id, "dataSourceMSSQL" perhaps. Bind them up to different properties file if you don't want to hard coded property values. For simplicity you can just hard coded it (not recommended). If you chose otherwise, you need to create another properties file to store mssql connection properties, perhaps jdbc-mssql.properties and add it into propertyConfigurer list. This also require you to make changes to your pom file to include custom settings under <!-- Database settings --> section. This can be a bit complicated.
Create another "sessionFactory" bean definition in applicationContext-dao.xml with MSSQL specific values such as hibernate dialect etc. and binds it to "dataSourceMSSQL" as dataSource property ref. Give it a different bean id perhaps, "sessionFactoryMSSQL".
Wire your DAOs which require the new sessionFactory i.e.:
#Autowired private SessionFactory sessionFactoryMSSQL;
Hope that will work for you.
So my scenario drilled down to the essence is as follows:
Essentially, I have a config file containing a set of SQL queries whose result sets need to be exported as CSV files.
Since some queries may return billions of rows, and because something may interrupt the process (bug, crash, ...), I want to use a framework such as spring batch, which gives me restartabilty and job monitoring.
I am using a file based H2 database for persisting spring batch jobs.
So, here are my questions:
Upon creating a Job, I need to provide my RowMapper some initial configuration. So what happens when a job needs to be restarted after a e.g. crash? Concretly:
Is the state of the RowMapper automatically persisted, and upon restart Spring batch will try to restore the object from its database, or
will the RowMapper object be used that is part of the original spring batch XML config file, or
I have to maintain the RowMapper's state using the step's/job's ExecutionContext?
Above question is related to whether there is magic going on when using the spring batch XML configuration, or whether I could as well create all these beans in a programmatic way:
Since I need to parse my own config format into a spring batch job config, I rather just use spring batch's Java classes (beans) and fill them out appropriately, rather attempting to manually write out valid XML. However, if my Job crashes, I would create all the beans myself again. Does spring batch automagically restore the Job state from its database?
If I really need XML, is there a way to serialize a spring-batch JobRepository (or one of these objects) as a spring batch XML config?
Right now, I tried to configure my Step with the following code - but I am unsure if this is the proper way to do this:
Is TaskletStep the way to go?
Is the way I create the chunked reader/writer correct, or is there some other object which I should use instead?
I would have assumed that opening of the reader and writer would occur automatically as part of the JobExecution, but if I don't open these resources prior to running the Job, I get an exception telling me that I need to open them first. Maybe I need to create some other object that manages the resoures (jdbc connection and file handle)?
JdbcCursorItemReader<Foobar> itemReader = new JdbcCursorItemReader<Foobar>();
itemReader.setSql(sqlStr);
itemReader.setDataSource(dataSource);
itemReader.setRowMapper(rowMapper);
itemReader.afterPropertiesSet();
ExecutionContext executionContext = new ExecutionContext();
itemReader.open(executionContext);
FlatFileItemWriter<String> itemWriter = new FlatFileItemWriter<String>();
itemWriter.setLineAggregator(new PassThroughLineAggregator<String>());
itemWriter.setResource(outResource);
itemWriter.afterPropertiesSet();
itemWriter.open(executionContext);
int commitInterval = 50000;
CompletionPolicy completionPolicy = new SimpleCompletionPolicy(commitInterval);
RepeatTemplate repeatTemplate = new RepeatTemplate();
repeatTemplate.setCompletionPolicy(completionPolicy);
RepeatOperations repeatOperations = repeatTemplate;
ChunkProvider<Foobar> chunkProvider = new SimpleChunkProvider<Foobar>(itemReader, repeatOperations);
ItemProcessor<Foobar, String> itemProcessor = new ItemProcessor<Foobar, String>() {
/* Custom implemtation */ };
ChunkProcessor<Foobar> chunkProcessor = new SimpleChunkProcessor<Foobar, String>(itemProcessor, itemWriter);
Tasklet tasklet = new ChunkOrientedTasklet<QuadPattern>(chunkProvider, chunkProcessor); //new SplitFilesTasklet();
TaskletStep taskletStep = new TaskletStep();
taskletStep.setName(taskletName);
taskletStep.setJobRepository(jobRepository);
taskletStep.setTransactionManager(transactionManager);
taskletStep.setTasklet(tasklet);
taskletStep.afterPropertiesSet();
job.addStep(taskletStep);
Most of you questions are really complex and can be difficult give a good answer without write a long paper.
I'm new with spring-batch as you, and I found a lot of really useful info - and all the answers to your questions - reading Spring batch in action: it's completed, well explained, full of example and cover all aspects of framework (reader/writer/processor, job/tasklet/chunk lifecycle/persistence, tx/resources management, job flow, integration with other service, partitioning, restarting/retry, failure management and a lot of interesting things).
Hope to help
I've finished building my blog using EF and Code First.
EF was running against my local SQL Express instance, with [DBO] schema.
Now i want to publish the blog, and i have done the following :
Generetade the scripts for the tables and all objects from SQL Express and change [dbo] to my [administrator] schema from my server.
Ran the scripts against the server. No issues, all objects were created an populated just fine.
I have modified Webconfig and added my BlogContext connection string to point to the server not local sql express.
Published the site.
The error i am getting is : Invalid object name 'dbo.Articles'. - where Articles is one of my entities. It resides on my sql server, [Administrator].Articles.
As far as i can tell EF still thinks im using the DBO schema. Although i have added the connection string to point to administrator user.
How can i change the schema that EF thinks it should use?
EF will use dbo schema if you didn't configure the schema explicitly through data annotations or fluent API.
[Table("MyTable", "MySchema")]
public class MyEntity
{
}
Or
modelBuidler.Entity<MyEntity>().ToTable("MyTable", "MySchema");
Just for searchers: I am just working with EF5 .NET4.5, and
[Table("MyTable", "MySchema")]
does not work. Even if VS2012 shows there is an overload which takes 2 parameters, on build it gives the error: 'System.ComponentModel.DataAnnotations.Schema.TableAttribute' does not contain a constructor that takes 2 arguments.
But the code mapping works just fine.
We're running into a small problem deploying a web application to another environment.
We created the application's db using Entity Framework Code First approach (db automatic created from Model).
In this development environment, we are using integrated security and the tables are created under the dbo user. The tables are like
[dbo].[myTable]
For our other environment, we are using username/password authentication for the DB.
We scripted the tables and created them on the DB. So they are now named like
[myDbUser].[myTable]
When running the application, we encounter always the problem
Invalid object name 'dbo.myTable'.
Seems like the code is still trying to look for a dbo table, which is not present and thus fails.
Can anyone shed some light on this problem? Where does Entity Framework gets this dbo prefix from?
Thanks
Specify schema explicitly:
[Table("Users", Schema = "dbo")]
public class User { .. }
Or specify default db schema for your user - 'dbo'
To specify schema in fluent
protected override void OnModelCreating(DbModelBuilder modelBuilder)
modelBuilder.Entity<ClassName>().ToTable("TableName", "SchemaName");
I ran into this issue recently as well as we support several different schemas with the same model. What I basically came up with was the passing the schema name to the classes/methods that map the model. So for example, EntityTypeConfiguration subclasses take the schema name as a constructor argument, and pass it along with the hard-coded string to ToTable().
See here for a more detailed explanation: https://stackoverflow.com/a/14782001/243607
I've written an ASP.Net MVC 3 application using the Code First paradigm whereby when I make a change to the model the Entity Framework automatically attempts to re-create the underlying SQL Server Database via DROP and CREATE statements. The problem is the application is hosted on a 3rd party remote server which limits the number of databases I can have and does not seem to allow me to programmatically execute "CREATE DATABASE..." statements as I gather from this error message:
CREATE DATABASE permission denied in database 'master'.
Is there any way to stop the Entity Framework from dropping and attempting to re-create the whole database and instead make it simply drop the tables and re-create them?
After creating the database manually and running the application I also get the following error I guess as the Entity Framework tries to modify the database:
Model compatibility cannot be checked because the database does not contain model metadata. Ensure that IncludeMetadataConvention has been added to the DbModelBuilder conventions.
UPDATE: Found this gem through google, it sounds like its exactly what you need: http://nuget.org/Tags/IDatabaseInitializer
You can use a different database initializer. Lets say your context is called SampleContext then your constructor would look like this:
public SampleContext()
{
System.Data.Entity.Database.SetInitializer(new CreateDatabaseIfNotExists<SampleContext>());
}
Note that the above is the default initializer. You will probably need to create your own custom initializer by implementing IDatabaseInitializer. Theres some good info here: http://sankarsan.wordpress.com/2010/10/14/entity-framework-ctp-4-0-database-initialization/
Using EF 4.3 with Migrations you do not get this behavior - at least I have not seen it. But I also have this set in my code -
public sealed class DbConfiguration : DbMigrationsConfiguration<DatabaseContext>
{
public DbConfiguration()
{
AutomaticMigrationsEnabled = false;
}
}