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public abstract class RecordORMHelper
{
/// <summary>
/// 对象操作的数据表名称
/// </summary>
public abstract string TableName
{
get ;
}
/// <summary>
/// 从数据读取器读取数据创建一个记录对象
/// </summary>
/// <param name="reader">数据读取器</param>
/// <returns>读取的数据</returns>
public object ReadRecord( System.Data.IDataReader reader )
{
int[] indexs = GetFieldIndexs( reader );
return InnerReadRecord( reader ,indexs );
}
/// <summary>
/// 从数据读取器读取数据创建若干个记录对象
/// </summary>
/// <param name="reader">数据读取器</param>
/// <param name="MaxRecordCount">允许读取的最大的记录个数，为0则无限制</param>
/// <returns>读取的数据对象列表</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>
/// 从一个数据读取器中读取一条记录对象,必须重载
/// </summary>
/// <param name="reader">数据读取器</param>
/// <param name="FieldIndexs">字段序号列表</param>
/// <returns>读取的记录对象</returns>
protected abstract object InnerReadRecord( System.Data.IDataReader reader , int[] FieldIndexs );
/// <summary>
/// 为删除记录而初始化数据库命令对象
/// </summary>
/// <param name="cmd">数据库命令对象</param>
/// <param name="objRecord">实体对象实例</param>
/// <returns>添加的SQL参数个数</returns>
public abstract int FillDeleteCommand( System.Data.IDbCommand cmd , object objRecord );
/// <summary>
/// 为插入记录而初始化数据库命令对象
/// </summary>
/// <param name="cmd">数据库命令对象</param>
/// <param name="objRecord">实体对象实例</param>
/// <returns>添加的SQL参数个数</returns>
public abstract int FillInsertCommand( System.Data.IDbCommand cmd , object objRecord );
/// <summary>
/// 为更新数据库记录而初始化数据库命令对象
/// </summary>
/// <param name="cmd">数据库命令对象</param>
/// <param name="objRecord">实体对象实例</param>
/// <returns>添加的SQL参数个数</returns>
public abstract int FillUpdateCommand( System.Data.IDbCommand cmd , object objRecord );
/// <summary>
/// 字段列表数组
/// </summary>
protected abstract string[] RecordFieldNames
{
get ;
}
/// <summary>
/// 针对特定的数据读取器获得实体对象的各个属性对应的数据栏目的编号
/// </summary>
/// <param name="reader">数据读取器</param>
/// <returns>编号列表</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>
/// 连接多个字符串,各个字符串之间用逗号分隔，本函数会在动态生成的派生类中使用
/// </summary>
/// <param name="strs">字符串集合</param>
/// <returns>连接所得的大字符串</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>
/// 判断两个字段名是否等价
/// </summary>
/// <param name="name1">字段名1</param>
/// <param name="name2">字段名2</param>
/// <returns>true:两个字段名等价 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();
// 进行不区分大小写的比较
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 从数据库读取的原始数据转换为指定数据类型的函数群，本函数会在动态生成的派生类中使用
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 );
}
其他的 ConvertTo 函数
#endregion
/// <summary>
/// 将日期数据转换为数据库中的格式,本函数会在动态生成的派生类中使用.
/// </summary>
/// <param name="Value">日期数据</param>
/// <param name="Format">保存格式化字符串</param>
/// <returns>转换后的数据</returns>
protected object DateTimeToDBValue( DateTime Value , string Format )
{
if( Format != null || Format.Length > 0 )
{
return Value.ToString( Format );
}
else
{
return Value ;
}
}
}//public abstract class RecordORMHelper
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