Ent Lib 2.0 DAAB添加MySql扩展 MySql5.0.27+MySql .Net Connector 5.0.2beta

1. 准备
    注释掉Data项目GlobalAssemblyInfo.cs文件里[assembly: CLSCompliant(true)]这一句。因为引用MySql.Data.dll中有不符合CLS规范的地方。
    确保安装了MySql .Net Connector，为Data项目添加MySql.Data.dll的引用。
    其它的一些预先的测试参考：DAAB MySql支持测试(Proc+DataSet更新) 5.0.27+.Net Connector 5.0.2beta。

2. 扩展
    经过前期的测试，MySql.Data基本完全跟System.Data.SqlClient操作方式一样，因此DAAB中MySql的扩展也只需要针对MySql，仿照SqlDatabase进行扩展就可以了。
    在Data项目中添加MySql目录，并在目录下添加下面的两个文件，编译，或者另外建立一个工程来做（为了简短起见，注视都去掉了）。

namespace Microsoft.Practices.EnterpriseLibrary.Data.MySql
{
    using Microsoft.Practices.EnterpriseLibrary.Common.Configuration;
    using Microsoft.Practices.EnterpriseLibrary.Data.Configuration;

    public class MySqlDatabaseAssembler : IDatabaseAssembler
    {
        public Database Assemble(string name, ConnectionStringSettings connectionStringSettings, IConfigurationSource configurationSource)
        {
            return new MySqlDatabase(connectionStringSettings.ConnectionString);
        }
    }
}

namespace Microsoft.Practices.EnterpriseLibrary.Data.MySql
{
    using System;
    using System.Data;
    using System.Data.Common;
    using MySql.Data.MySqlClient;
    using Microsoft.Practices.EnterpriseLibrary.Data.Configuration;

    [DatabaseAssembler(typeof(MySqlDatabaseAssembler))]
    public class MySqlDatabase : Database
    {
        private const char _parameterToken = '?';

        public MySqlDatabase(string connectionString)
            : base(connectionString, MySqlClientFactory.Instance)
        {
        }

        protected override void DeriveParameters(DbCommand discoveryCommand)
        {
            MySqlCommandBuilder.DeriveParameters((MySqlCommand)discoveryCommand);
        }

        public override string BuildParameterName(string name)
        {
            if (name[0] != _parameterToken)
            {
                return name.Insert(0, new string(_parameterToken, 1));
            }
            return name;
        }

        protected override void SetUpRowUpdatedEvent(DbDataAdapter adapter)
        {
            ((MySqlDataAdapter)adapter).RowUpdated += new MySqlRowUpdatedEventHandler(OnMySqlRowUpdated);
        }

        private void OnMySqlRowUpdated(object sender, MySqlRowUpdatedEventArgs args)
        {
            if (args.RecordsAffected == 0)
            {
                if (args.Errors != null)
                {
                    args.Row.RowError = Resources.ExceptionMessageUpdateDataSetRowFailure;
                    args.Status = UpdateStatus.SkipCurrentRow;
                }
            }
        }

        public virtual void AddParameter(DbCommand command, string name, MySqlDbType dbType, int size, ParameterDirection direction
            , bool nullable, byte precision, byte scale, string sourceColumn, DataRowVersion sourceVersion, object value)
        {
            DbParameter parameter = CreateParameter(name, dbType, size, direction, nullable, precision, scale, sourceColumn, sourceVersion, value);
            command.Parameters.Add(parameter);
        }

        public void AddParameter(DbCommand command, string name, MySqlDbType dbType
            , ParameterDirection direction, string sourceColumn, DataRowVersion sourceVersion, object value)
        {
            AddParameter(command, name, dbType, 0, direction, false, 0, 0, sourceColumn, sourceVersion, value);
        }

        public void AddOutParameter(DbCommand command, string name, MySqlDbType dbType, int size)
        {
            AddParameter(command, name, dbType, size, ParameterDirection.Output, true, 0, 0, String.Empty, DataRowVersion.Default, DBNull.Value);
        }

        public void AddInParameter(DbCommand command, string name, MySqlDbType dbType)
        {
            AddParameter(command, name, dbType, ParameterDirection.Input, String.Empty, DataRowVersion.Default, null);
        }

        public void AddInParameter(DbCommand command, string name, MySqlDbType dbType, object value)
        {
            AddParameter(command, name, dbType, ParameterDirection.Input, String.Empty, DataRowVersion.Default, value);
        }

        public void AddInParameter(DbCommand command, string name, MySqlDbType dbType, string sourceColumn, DataRowVersion sourceVersion)
        {
            AddParameter(command, name, dbType, 0, ParameterDirection.Input, true, 0, 0, sourceColumn, sourceVersion, null);
        }

        protected DbParameter CreateParameter(string name, MySqlDbType dbType, int size, ParameterDirection direction
            , bool nullable, byte precision, byte scale, string sourceColumn, DataRowVersion sourceVersion, object value)
        {
            MySqlParameter param = base.CreateParameter(name) as MySqlParameter;
            ConfigureParameter(param, name, dbType, size, direction, nullable, precision, scale, sourceColumn, sourceVersion, value);
            return param;
        }

        protected virtual void ConfigureParameter(MySqlParameter param, string name, MySqlDbType dbType, int size, ParameterDirection direction
            , bool nullable, byte precision, byte scale, string sourceColumn, DataRowVersion sourceVersion, object value)
        {
            param.MySqlDbType = dbType;
            param.Size = size;
            param.Value = (value == null) ? DBNull.Value : value;
            param.Direction = direction;
            param.IsNullable = nullable;
            param.SourceColumn = sourceColumn;
            param.SourceVersion = sourceVersion;
        }
    }
}

3. 测试
没有使用NUnit，也没有使用MS的Test，直接建立一个web项目大致测试了一下。测试用的表、存储过程在DAAB MySql支持测试(Proc+DataSet更新) 5.0.27+.Net Connector 5.0.2beta中。
在web.config文件里面加上下面的配置，注意将MySql连接字符串相关参数配置正确。

为web项目添加Microsoft.Practices.EnterpriseLibrary.Data.dll的引用，web项目引用的命名空间：

using Microsoft.Practices.EnterpriseLibrary.Data;

using Microsoft.Practices.EnterpriseLibrary.Data.MySql;

using MySql.Data.MySqlClient;

部分测试代码如下：

private void displayBySqlText()
{
    Database database=DatabaseFactory.CreateDatabase("MySqlTest");
    string sql = "select * from test.tbluser where tbluser.UserCode like " +
        database.BuildParameterName("UserCode") + " and tbluser.UserName like " +
        database.BuildParameterName("UserName");
    DbCommand command = database.GetSqlStringCommand(sql);
    //database.AddParameter()方法会自动调用database.BuildParameterName()进行处理
    database.AddParameter(command, "UserCode", DbType.String, ParameterDirection.Input, "",
        DataRowVersion.Default, this.TextBox1.Text + "%");
    database.AddParameter(command, "UserName", DbType.String, ParameterDirection.Input, "",
        DataRowVersion.Default, "%" + this.TextBox2.Text + "%");
    DataSet ds = database.ExecuteDataSet(command);

    this.GridView1.DataSource = ds;
    this.GridView1.DataBind();
}

private void displayByProcedure()
{
    Database db = DatabaseFactory.CreateDatabase("MySqlTest");
    DataSet ds = db.ExecuteDataSet("SP_QueryUser"
        , new object[] { this.TextBox1.Text.Trim() + "%", "%" + this.TextBox2.Text.Trim() + "%" });

    this.GridView1.DataSource = ds;
    this.GridView1.DataBind();
}

4. 评论
    DAAB对数据库操作封装一下之后，用起来是简单了一些。
    使用DAAB，如果你写的SQL，或者是生成的SQL符合SQL92、99等标准，大部分情况下都能满足多数据库支持要求。从上面的测试代码可以看到，一定程度上你不需要关注使用的什么数据库类型。
    如果你想多数据库支持方案里面支持更多的一些特性，如更丰富的语法特性、分页、系统函数等，你还得在DAAB的基础上对数据库再次封装扩展。

posted on 2006-12-27 11:51 riccc 阅读(3719) 评论(5) 编辑收藏举报

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Ent Lib 2.0 DAAB添加MySql扩展 MySql5.0.27+MySql .Net Connector 5.0.2beta

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