企业库数据库访问模块通过抽象工厂模式,允许用户通过简单的配置选择不同的数据库作为程序的数据源,大大解决了切换数据库时带来的麻烦.因为我本机只安装了SQL Server 2005,所以在此只做SQL的演示,需要深究的朋友可以访问以下网站:
http://msdn.microsoft.com/en-us/library/ff664408%28v=PandP.50%29.aspx
企业库数据库访问模块的几大功能:
1. 最简单的功能,通过ExecuteNonQuery.方法执行SQL语句.
2. 执行ExecuteDataSet,返回DataSet类型的数据集.
3. 执行ExecuteScalar,获取返回的第一行第一列的信息.
4. 执行存储过程.
5. 通过代码实现事务.
6. 通过DataSet更新数据库.
7. 返回值XML化.
8. 将返回的数据对象化.
9. 异步访问数据库.
以上的功能我会在下面一一介绍,测试程序我已打包,大家可以点击这里下载.
下面介绍如何使用Microsoft Enterprise Library 5.0中的数据库访问模块.
1. 首先创建一个测试数据库,创建数据库的SQL文件我打包在压缩包里了,大家可以点击上面的下载链接下载.执行完SQL文件后,可以看到我们创建好的TestDB数据库:
2. 下载安装好MicrosoftEnterprise Library 5.0,然后在运行EntLibConfig.exe,选择Blocks菜单 ,单击 AddDatabase Settings .
3. 配置好文件之后保存为App.config文件,并添加到创建好的应用程序中.并添加相应的引用,在此我不再多讲,大家下载我打包好的程序运行即可看到
4. 下面来介绍我在应用程序中实现的各个功能:
(1) 通过ExecuteNonQuery.方法执行SQL语句:
/// summary
/// 执行ExecuteNonQuery
/// /summary
private void ExecuteNonQuery_Click(object sender, EventArgs e)
{
db.ExecuteNonQuery(CommandType.Text, INSERT INTO [College] ([CollegeID],[Name]) values (6,\'体育学院\')
}
(2) 执行ExecuteDataSet,返回DataSet类型的数据集.
/// summary
/// 执行ExecuteDataSet,返回College列表
/// /summary
/// returns /returns
private void ExecuteDataSet_Click(object sender, EventArgs e)
{
string sql = select * from College
DbCommand dw = db.GetSqlStringCommand(sql);
dataGridView1.DataSource = db.ExecuteDataSet(dw).Tables[0];
}
(3) 执行ExecuteScalar,返回第一行第一列的值.
/// summary
/// 执行ExecuteScalar,返回第一行第一列的值
/// /summary
/// returns /returns
private void ExecuteScalar_Click(object sender, EventArgs e)
{
Database db = DatabaseFactory.CreateDatabase( ConnectionString
string sql = select [Name] from College where [CollegeID] = 1
DbCommand dc = db.GetSqlStringCommand(sql);
string str = 获取的学院名称为: + (string)db.ExecuteScalar(dc);
MessageBox.Show(str);
sql = select [CollegeID] from College where [CollegeID] = 1
dc = db.GetSqlStringCommand(sql);
str = 获取的学院ID为: + (int)db.ExecuteScalar(dc);
MessageBox.Show(str);
}
(4) 执行存储过程.
/// summary
/// 执行存储过程
/// /summary
private void StoredProcCommand_Click(object sender, EventArgs e)
{
DbCommand dc = db.GetStoredProcCommand( usp_College_LoadByID
db.AddInParameter(dc, @CollegeID , System.Data.DbType.Int32, 5);
dataGridView1.DataSource = db.ExecuteDataSet(dc).Tables[0];
}
(5) 通过代码实现事务.
/// summary
/// 事务
/// /summary
private void Transaction_Click(object sender, EventArgs e)
{
DbCommand dc1 = db.GetStoredProcCommand( usp_College_Insert
db.AddInParameter(dc1, @CollegeID , DbType.Int32, 7);
db.AddInParameter(dc1, @Name , DbType.String, 文旅学院
DbCommand dc2 = db.GetStoredProcCommand( usp_College_Insert
db.AddInParameter(dc2, @CollegeID , DbType.Int32, 7);
db.AddInParameter(dc2, @Name , DbType.String, 化工学院
using (DbConnection conn = db.CreateConnection())
{
conn.Open();
DbTransaction trans = conn.BeginTransaction();
try
{
//添加一个ID为7的学院
db.ExecuteNonQuery(dc1, trans);
//添加一个ID为7的学院,主键重复,事务将回滚
db.ExecuteNonQuery(dc2, trans);
//提交事务.
trans.Commit();
}
catch
{
//回滚
trans.Rollback();
}
conn.Close();
}
//查看数据库,数据未被添加,说明事务已回滚
ExecuteDataSet_Click(null, null);
}
(6) 通过DataSet更新数据库.
/// summary
/// 通过DataSet更新数据库
/// /summary
private void DataSetUpdate_Click(object sender, EventArgs e)
{
DataSet productsDataSet = new DataSet();
string sql = Select * From College
DbCommand cmd = db.GetSqlStringCommand(sql);
string CollegeTableName = College
//恢复原始数据
db.LoadDataSet(cmd, productsDataSet, CollegeTableName);
//获取数据表格
DataTable dTable = productsDataSet.Tables[CollegeTableName];
//添加一个新信息入DataSet中
DataRow addedRow = dTable.Rows.Add(new object[] { 8, 外国语学院 });
//修改一个原有数据
dTable.Rows[0][ Name ] = 国教院
//提供插入,更新,删除存储过程
DbCommand insertCommand = db.GetStoredProcCommand( usp_College_Insert
db.AddInParameter(insertCommand, @CollegeID , DbType.Int32, CollegeID , DataRowVersion.Current);
db.AddInParameter(insertCommand, @Name , DbType.String, Name , DataRowVersion.Current);
DbCommand deleteCommand = db.GetStoredProcCommand( usp_College_Delete
db.AddInParameter(deleteCommand, @CollegeID , DbType.Int32, CollegeID , DataRowVersion.Current);
DbCommand updateCommand = db.GetStoredProcCommand( usp_College_Update
db.AddInParameter(updateCommand, @CollegeID , DbType.Int32, CollegeID , DataRowVersion.Current);
db.AddInParameter(updateCommand, @Name , DbType.String, Name , DataRowVersion.Current);
//通过DataSet更新数据库
int rowsAffected = db.UpdateDataSet(productsDataSet, CollegeTableName, insertCommand, updateCommand, deleteCommand,
Microsoft.Practices.EnterpriseLibrary.Data.UpdateBehavior.Standard);
MessageBox.Show( 影响的行数: + rowsAffected);
}
(7) 返回值XML化.
/// summary
/// 返回值XML化
/// /summary
private void ReturnXML_Click(object sender, EventArgs e)
{
//使用 FOR XML AUTO 参数使得SQL返回XML格式的信息
SqlDatabase sqldb = (SqlDatabase)DatabaseFactory.CreateDatabase( ConnectionString
DbCommand cmd = sqldb.GetSqlStringCommand( SELECT * FROM College FOR XML AUTO
IEnumerable string productList;
using (var reader = sqldb.ExecuteXmlReader(cmd))
{
if (reader.IsStartElement())
{
var root = (XElement)XNode.ReadFrom(reader);
productList = root.Elements( CollegeID )
.Attributes( Name )
.Select(a = a.Value).ToArray();
MessageBox.Show(((XElement)root).ToString());
}
}
}
(8) 将返回的数据对象化.
/// summary
/// DataAsObject
/// /summary
private void DataAsObject_Click(object sender, EventArgs e)
{
//将返回的数据对象化
var results = db.ExecuteSprocAccessor College ( usp_College_LoadAll
MessageBox.Show(results.ElementAt(0).ToString());
}
(9) 异步访问数据库.
/// summary
/// 异步访问数据库
/// /summary
private void Async_Click(object sender, EventArgs e)
{
//创建新的数据库连接,属性必须添加:Asynchronous Processing=true
String connectionString = @ server=(local); database=TestDB; Integrated Security=true; Asynchronous Processing=true
Database Sqldb = new SqlDatabase(connectionString);
DbCommand cmd = Sqldb.GetStoredProcCommand( usp_College_LoadbyID
Sqldb.AddInParameter(cmd, @CollegeID , DbType.Int32, 1);
try
{
IAsyncResult result = Sqldb.BeginExecuteReader(cmd, MyEndExecuteCallback, Sqldb);
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
//当获取完毕执行该函数
private void MyEndExecuteCallback(IAsyncResult result)
{
try
{
Database Sqldb = (Database)result.AsyncState;
IDataReader reader = db.EndExecuteReader(result);
College c = new College((int)reader[0], (string)reader[1]);
MessageBox.Show(c.ToString());
}
catch(Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
出处:http://www.cnblogs.com/huangcong/archive/2010/05/31/1748672.html 请输
本文版权归作者和博客园共有,欢迎转载,但未经作者同意必须保留此段声明,且在文章页面明显位置给出原文连接,否则保留追究法律责任的权利。
本文链接: http://accessmylibrary.immuno-online.com/view-727039.html