Question

I’m looking for a tutorial, guidance or software that can generate simple POCO’s for some SQL Server tables for use in ASP.NET MVC. Something like this:

1) Keep a list of the table names in the SQL Server database that should have a POCO generated

2) Feed the list to some program

3) The program generates a simple POCO (more like DTO) in a single .cs file, or appends to a Poco.cs. Either way, it doesn’t matter.

For example:

public class MyDto
{
    public int Id { get; set; }
    public string Name { get; set; }
    public bool? IsMale {get; set;}
}

4) Run the program whenever I want to re-generate the POCO’s

The program could be WinForm, commandline, or something else. It doesn’t matter.

Answer 1

I have wanted to answer this but been busy.

I have created a simple example on how to read a database schema and generate classes and properties from this.

Basically you should be able to cutnpaste this into a TT file (see Oleg Sychs blog on how to get started), update the connection string and save to execute the template.

I don’t claim that this is a complete sample but it could serve as a starting point for you:

  <#@ template   language    = "C#"                           #>
  <#@ assembly   name        = "Microsoft.CSharp"             #>
  <#@ assembly   name        = "System.Core"                  #>
  <#@ assembly   name        = "System.Data"                  #>
  <#@ import     namespace   = "System.Collections.Generic"   #>
  <#@ import     namespace   = "System.Dynamic"               #>
  <#@ import     namespace   = "System.Linq"                  #>
  <#@ import     namespace   = "System.Data.SqlClient"        #>

  <#
     var namespaceName    = "Poco2";
     // Update the connection string to something appropriate
     var connectionString = @"Data Source=localhost\SQLExpress;Initial Catalog=MyTest;Integrated Security=True";
  #>

  <#
     using (var db = new SqlConnection (connectionString))
     using (var cmd = db.CreateCommand ())
     {
        db.Open();
        var tables              = ReadRows (cmd, "SELECT * FROM sys.tables").ToArray ();

        var columns             = ReadRows (cmd, "SELECT * FROM sys.columns").ToLookup (k => k.object_id);

        var indexes             = ReadRows (cmd, "SELECT * FROM sys.indexes").ToLookup (k => k.object_id);
        var indexColumns        = ReadRows (cmd, "SELECT * FROM sys.index_columns").ToLookup (k => k.object_id);

        var foreignKeys         = ReadRows (cmd, "SELECT * FROM sys.foreign_keys").ToArray ();
        var foreignKeyColumns   = ReadRows (cmd, "SELECT * FROM sys.foreign_key_columns").ToArray ();
  #>
  namespace <#=namespaceName#>
  {
     using System;
     using System.Data.Linq.Mapping;

  <#
        foreach (var table in tables)
        {         
  #>
     [Table]
     partial class <#=table.name#>
     {
  <#
           IEnumerable<dynamic> tc = columns[table.object_id];
           var tableColumns = tc.OrderBy (r => r.column_id).ToArray ();          

           IEnumerable<dynamic> ti = indexes[table.object_id];
           var tableIndexes = ti.ToArray ();          

           var primaryKeyIndex = tableIndexes.FirstOrDefault (i => i.is_primary_key);
           var primaryKeyColumns = new Dictionary<dynamic, dynamic> ();
           if (primaryKeyIndex != null)
           {
              IEnumerable<dynamic> pc = indexColumns[table.object_id];
              primaryKeyColumns = pc
                 .Where (c => c.index_id == primaryKeyIndex.index_id)
                 .ToDictionary (c => c.column_id, c => c.key_ordinal)
                 ;
           }

           foreach (var tableColumn in tableColumns)
           {
              var type = MapToType (tableColumn.user_type_id, tableColumn.max_length, tableColumn.is_nullable);

  #>
        [Column (IsPrimaryKey = <#=primaryKeyColumns.ContainsKey (tableColumn.column_id) ? "true" : "false"#>)]
        public <#=type#> <#=tableColumn.name#> {get;set;}

  <#
           }
  #>

     }
  <#
        }
  #>
  }
  <#
     }
  #>

  <#+

     struct DataType
     {     
        public readonly int     SizeOf;
        public readonly string  SingularType;
        public readonly string  PluralType;

        public DataType (
           int sizeOf,
           string singularType,
           string pluralType = null
           )
        {
           SizeOf         = sizeOf;
           SingularType   = singularType;
           PluralType     = pluralType ?? (singularType + "[]");
        }

     }
     static Dictionary<int, DataType> dataTypes = new Dictionary<int, DataType>
        {
           {61   , new DataType (8,  "DateTime"            )},
           {127  , new DataType (8,  "long"                )},
           {165  , new DataType (1,  "byte"                )},
           {231  , new DataType (2,  "char"    ,  "string" )},
        };

     static string MapToType (int typeId, int maxLength, bool isNullable)
     {
        DataType dataType;

        if (dataTypes.TryGetValue (typeId, out dataType))
        {
           var length = maxLength > 0 ? (maxLength / dataType.SizeOf) : int.MaxValue;
           if (length > 1)
           {
              return dataType.PluralType;
           }
           else
           {
              return dataType.SingularType + (isNullable ? "?" : "");
           }
        }
        else
        {
           return "UnknownType_"+ typeId;
        }
     }

     static IEnumerable<dynamic> ReadRows (SqlCommand command, string sql)
     {
        command.CommandText = sql ?? "";

        using (var reader = command.ExecuteReader())
        {
           while (reader.Read())
           {
              var dyn = new ExpandoObject ();
              IDictionary<string, object> dic = dyn;

              for (var iter = 0; iter < reader.FieldCount; ++iter)
              {
                    dic[reader.GetName(iter) ?? ""] = reader.GetValue(iter);
              }

              yield return dyn;
           }

        }
     }


  #>