Using entity framework on multiple databases

Question

I am writing a payroll system that will integrate with a pre-existing system. The original system had a master database that handled user management and some global configur

Answer 1

EF6 has better support for multiple DB access from Same context. Here is a snippet from EF5. Managing the database initializer setting prior is important. You may not want to trigger ANY migrations. i.e, use this before

Database.SetInitializer(new ContextInitializerNone());

but to answer the question: Yes you can

var conn = GetSqlConn4DbName(dataSource,dbName );
var ctx = new MyDbContext(conn,true);



public DbConnection GetSqlConn4DbName(string dataSource, string dbName) {
        var sqlConnStringBuilder = new SqlConnectionStringBuilder();
        sqlConnStringBuilder.DataSource = String.IsNullOrEmpty(dataSource) ? DefaultDataSource : dataSource;
        sqlConnStringBuilder.IntegratedSecurity = true;
        sqlConnStringBuilder.MultipleActiveResultSets = true;

        var sqlConnFact = new SqlConnectionFactory(sqlConnStringBuilder.ConnectionString);
        var sqlConn = sqlConnFact.CreateConnection(dbName);
        return sqlConn;
    }


 public class ContextInitializerNone : IDatabaseInitializer where TContext : DbContext
{
    public void InitializeDatabase(TContext context) {  }
}

Also see StackOverflow answer using migration, sample code, and dynamic db connection