Microsoft Enterprise Library 5.0 系列(五) Data Access Application Block
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()); } }
作者： 小聪崽的一切
出处： http://www.cnblogs.com/huangcong/
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。
出处： http://www.cnblogs.com/huangcong/
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。