' clsDataAccessOper 该类是所有数据访问类的父类

' by YuJun

‘ www.hahaIT.com

‘ hahasoft@msn.com



Public Class clsDataAccessOper



' 当Update,Delete,Add方法操作失败返回 False 时，记录出错的信息

Public Shared ModifyErrorString As String



Private Shared Keys As New Hashtable



' 数据库连接字符串

Public Shared Property ConnectionString() As String

Get

Return SqlHelper.cnnString.Trim

End Get

Set(ByVal Value As String)

SqlHelper.cnnString = Value.Trim

End Set

End Property



' Update 不更新主键，包括联合主键

Public Shared Function Update(ByVal o As Object) As Boolean

ModifyErrorString = ""

Try

If CType(SqlHelper.ExecuteNonQuery(SqlHelper.cnnString, CommandType.Text, SQLBuilder.Exists(o)), Int64) = 0 Then

Throw New Exception("该记录不存在!")

End If

Catch ex As Exception

Throw ex

End Try



Try

SqlHelper.ExecuteNonQuery(SqlHelper.cnnString, CommandType.Text, SQLBuilder.Update(o))

Catch ex As Exception

ModifyErrorString = ex.Message

Return False

End Try

Return True

End Function



' Delete 将忽略

Public Shared Function Delete(ByVal o As Object) As Boolean

ModifyErrorString = ""

Try

SqlHelper.ExecuteNonQuery(SqlHelper.cnnString, CommandType.Text, SQLBuilder.Delete(o))

Catch ex As Exception

ModifyErrorString = ex.Message

Return False

End Try

Return True

End Function



' Add 方法将忽略自动增加值的主键

Public Shared Function Add(ByVal o As Object) As Boolean

ModifyErrorString = ""

Try

SqlHelper.ExecuteNonQuery(SqlHelper.cnnString, CommandType.Text, SQLBuilder.Add(o))

Catch ex As Exception

ModifyErrorString = ex.Message

Return False

End Try

Return True

End Function



' 通用数据库查询方法

' 重载方法用于明确指定要操作的数据库表名称

' 否则会以 ReturnType 的类型描述得到要操作的数据库表的名称 eg: ReturnType="clsRooms" ,得道 TableName="tbl_Rooms"



' 该查询方法将查询条件添加到 Keys(HashTable) 中，然后调用 Select 方法返回 对象的集合

' 当Keys包含特殊键时，将要处理的是复杂类型的查询,见 SQLBuilder 的 ComplexSQL 说明

' 该方法可以拓展数据访问类的固定查询方法



Public Overloads Shared Function [Select](ByVal ReturnType As Type) As ArrayList

Dim tableName As String

tableName = ReturnType.Name

Dim i As Int16

i = tableName.IndexOf("cls") + 3

tableName = "tbl_" & tableName.Substring(i, tableName.Length - i)

Return [Select](ReturnType, tableName)

End Function



Public Overloads Shared Function [Select](ByVal ReturnType As Type, ByVal TableName As String) As ArrayList

Dim alOut As New ArrayList



Dim dsDB As New Data.DataSet

dsDB.ReadXml(clsPersistant.DBConfigPath)

Dim xxxH As New Hashtable

Dim eachRow As Data.DataRow

For Each eachRow In dsDB.Tables(TableName).Rows

If Keys.Contains(CType(eachRow.Item("name"), String).ToLower.Trim) Then

xxxH.Add(CType(eachRow.Item("d