基礎 類型RecordORMHelper
本類型屬於ORM框架的底層模塊。其代碼為
public abstract class RecordORMHelper
{
/// <summary>
/// 對象操作的數據表名稱
/// </summary>
public abstract string TableName
{
get ;
}
/// <summary>
/// 從數據讀取器讀取數據創建一個記錄對象
/// </summary>
/// <param name="reader">數 據讀取器</param>
/// <returns>讀取的數據 </returns>
public object ReadRecord( System.Data.IDataReader reader )
{
int[] indexs = GetFIEldIndexs( reader );
return InnerReadRecord( reader ,indexs );
}
/// <summary>
/// 從數據讀取器讀取數據創建若干個記錄對象
/// </summary>
/// <param name="reader">數據讀取器</param>
/// <param name="MaxRecordCount">允許讀取的最大的記錄個數，為0則無限制</param>
/// <returns>讀取的數據對象列表</returns>
public System.Collections.ArrayList ReadRecords( System.Data.IDataReader reader , int MaxRecordCount )
{
System.Collections.ArrayList list = new System.Collections.ArrayList();
int[] indexs = GetFIEldIndexs( reader );
while( reader.Read())
{
object record = InnerReadRecord( reader , indexs );
list.Add( record );
if( MaxRecordCount > 0 && list.Count >= MaxRecordCount )
{
break;
}
}//while
return list ;
}
/// <summary>
/// 從一個數據讀取器中讀取一條記錄對象,必須重載
/// </summary>
/// <param name="reader">數據讀取器</param>
/// <param name="FIEldIndexs">字段序號列表</param>
/// <returns>讀取的記錄對象</returns>
protected abstract object InnerReadRecord( System.Data.IDataReader reader , int[] FIEldIndexs );
/// <summary>
/// 為刪除記錄而初始化數據庫命令對象
/// </summary>
/// <param name="cmd">數據庫命令對象</param>
/// <param name="objRecord">實體對象實例</param>
/// <returns>添加的SQL參數個數</returns>
public abstract int FillDeleteCommand( System.Data.IDbCommand cmd , object objRecord );
/// <summary>
/// 為插 入記錄而初始化數據庫命令對象
/// </summary>
/// <param name="cmd">數據庫命令對象</param>
/// <param name="objRecord">實體對象實例</param>
/// <returns>添加的SQL參數個數</returns>
public abstract int FillInsertCommand( System.Data.IDbCommand cmd , object objRecord );
/// <summary>
/// 為更新數據庫記 錄而初始化數據庫命令對象
/// </summary>
/// <param name="cmd">數據庫命令對象</param>
/// <param name="objRecord">實體對象實例</param>
/// <returns>添加的SQL參數個數</returns>
public abstract int FillUpdateCommand( System.Data.IDbCommand cmd , object objRecord );
/// <summary>
/// 字段列表數組
/// </summary>
protected abstract string [] RecordFIEldNames
{
get ;
}
/// <summary>
/// 針對特定的數據 讀取器獲得實體對象的各個屬性對應的數據欄目的編號
/// </summary>
/// <param name="reader">數據讀取器 </param>
/// <returns>編號列表</returns>
private int[] GetFIEldIndexs( System.Data.IDataReader reader )
{
if( reader == null )
{
throw new ArgumentNullException ("reader");
}
string[] FieldNames = this.RecordFIEldNames ;
int[] indexs = new int[ FIEldNames.Length ] ;
int FieldCount = reader.FIEldCount ;
string[] names = new string[ FIEldCount ] ;
for( int iCount = 0 ; iCount < FIEldCount ; iCount ++ )
{
names[ iCount ] = reader.GetName( iCount ) ;
}
for( int iCount = 0 ; iCount < indexs.Length ; iCount ++ )
{
indexs[ iCount ] = -1 ;
string name = FIEldNames[ iCount ] ;
for( int iCount2 = 0 ; iCount2 < FIEldCount ; iCount2 ++ )
{
if( EqualsFIEldName( name , names[ iCount2 ] ))
{
indexs[ iCount ] = iCount2 ;
break;
}
}
}
for( int iCount = 0 ; iCount < FIEldCount ; iCount ++ )
{
string name = reader.GetName( iCount );
for( int iCount2 = 0 ; iCount2 < indexs.Length ; iCount2 ++ )
{
if( EqualsFieldName( name , FIEldNames[ iCount2 ] ))
{
indexs[ iCount2 ] = iCount ;
}
}
}
return indexs ;
}
/// <summary>
/// 連接多個字符串,各個字符串之間用逗號分隔，本函 數會在動態生成的派生類中使用
/// </summary>
/// <param name="strs">字符串集合</param>
/// <returns>連接所得的大字符串</returns>
protected string ConcatStrings( System.Collections.IEnumerable strs )
{
System.Text.StringBuilder myStr = new System.Text.StringBuilder();
foreach( string str in strs )
{
if( myStr.Length > 0 )
{
myStr.Append(",");
}
myStr.Append( str );
}//foreach
return myStr.ToString();
}
/// <summary>
/// 判斷兩個字段名是否等價
/// </summary>
/// <param name="name1">字 段名1</param>
/// <param name="name2">字段名 2</param>
/// <returns>true:兩個字段名等價 false:字 段名不相同</returns>
private bool EqualsFIEldName( string name1 , string name2 )
{
if( name1 == null || name2 == null )
{
throw new ArgumentNullException("name1 or name2");
}
name1 = name1.Trim();
name2 = name2.Trim();
// 進行不區分大小寫的比較
if( string.Compare( name1 , name2 , true ) == 0 )
{
return true ;
}
int index = name1.IndexOf(".");
if( index > 0 )
{
name1 = name1.Substring( index + 1 ).Trim();
}
index = name2.IndexOf(".");
if( index > 0 )
{
name2 = name2.Substring( index + 1 ).Trim();
}
return string.Compare( name1 , name2 , true ) == 0 ;
}
#region 從數據庫讀取的原始數據轉 換為指定數據類型的函數群，本函數會在動態生成的派生類中使用
protected byte ConvertToByte( object v , byte DefaultValue )
{
if( v == null || DBNull.Value.Equals( v ))
return DefaultValue ;
else
return Convert.ToByte( v );
}
protected sbyte ConvertToSByte( object v , sbyte DefaultValue )
{
if( v == null || DBNull.Value.Equals( v ))
return DefaultValue ;
else
return Convert.ToSByte( v );
}
