/// <summary>
/// 删除若干条对象的数据
/// </summary>
/// <param name="Objects">对象列表</param>
/// <returns>删除的记录个数</returns>
public int DeleteObjects(System.Collections.IEnumerable Objects)
{
if (Objects == null)
{
throw new ArgumentNullException("Objects");
}
this.CheckBindInfo(Objects, true);
this.CheckConnetion();
int RecordCount = 0;
using (System.Data.IDbCommand cmd = myConnection.CreateCommand())
{
foreach (object obj in Objects)
{
TableBindInfo table = this.GetBindInfo(obj.GetType());
// 拼凑SQL语句
System.Collections.ArrayList values = new System.Collections.ArrayList();
string strSQL = BuildCondition(obj, values);
strSQL = "Delete From " + FixTableName(table.TableName) + " Where " + strSQL;
// 设置SQL命令对象
cmd.Parameters.Clear();
cmd.CommandText = strSQL;
foreach (object v in values)
{
System.Data.IDbDataParameter p = cmd.CreateParameter();
p.Value = v;
cmd.Parameters.Add(p);
}
// 执行SQL，删除记录
RecordCount += cmd.ExecuteNonQuery();
}
}
return(RecordCount);
}
/// <summary>
/// 根据对象数值创建查询条件子SQL语句
/// </summary>
/// <param name="obj">对象</param>
/// <param name="values">SQL参数值列表</param>
/// <returns>创建的SQL语句字符串</returns>
private string BuildCondition(object obj, System.Collections.ArrayList values)
{
TableBindInfo table = this.GetBindInfo(obj.GetType());
// 拼凑查询条件SQL语句
System.Text.StringBuilder mySQL = new System.Text.StringBuilder();
foreach (FieldBindInfo field in table.Fields)
{
if (field.Attribute.Key)
{
object v = field.Property.GetValue(obj, null);
if (v == null || DBNull.Value.Equals(v))
{
throw new Exception("关键字段属性 " + field.Property.Name + " 未指定值");
}
if (mySQL.Length > 0)
{
mySQL.Append(" And ");
}
mySQL.Append(FixFieldName(field.FieldName));
mySQL.Append(" = ? ");
values.Add(field.ToDataBase(v));
}
} //foreach
if (mySQL.Length == 0)
{
throw new Exception("类型 " + obj.GetType().FullName + " 未能生成查询条件");
}
return(mySQL.ToString());
}
/// <summary>
/// 判断数据库中是否存在指定的对象
/// </summary>
/// <param name="obj">对象</param>
/// <returns>true:数据库中存在指定关键字的记录 false:数据库中不存在指定关键字的记录</returns>
public bool Contains(object obj)
{
if (obj == null)
{
throw new ArgumentNullException("obj");
}
this.CheckBindInfo(obj.GetType(), true);
this.CheckConnetion();
TableBindInfo table = this.GetBindInfo(obj.GetType());
System.Collections.ArrayList values = new System.Collections.ArrayList();
string strSQL = this.BuildCondition(obj, values);
bool result = false;
if (strSQL != null)
{
using (System.Data.IDbCommand cmd = myConnection.CreateCommand())
{
strSQL = "Select 1 from " + FixTableName(table.TableName) + " Where " + strSQL;
cmd.CommandText = strSQL;
foreach (object v in values)
{
System.Data.IDbDataParameter p = cmd.CreateParameter();
p.Value = v;
cmd.Parameters.Add(p);
}
object v2 = cmd.ExecuteScalar();
if (v2 != null && DBNull.Value.Equals(v2) == false)
{
result = (Convert.ToInt32(v2) == 1);
}
}
}
return(false);
}
/// <summary>
/// 读取指定类型的所有的对象
/// </summary>
/// <param name="ObjectType">记录对象类型</param>
/// <returns>读取的记录对象数组</returns>
public object[] ReadAllObjects(Type ObjectType)
{
if (ObjectType == null)
{
throw new ArgumentNullException("ObjectType");
}
this.CheckBindInfo(ObjectType, false);
TableBindInfo table = this.GetBindInfo(ObjectType);
string strSQL = "Select " + table.FieldNameList + " From " + FixTableName(table.TableName);
return(ReadObjects(strSQL, ObjectType, 0));
}
/// <summary>
/// 更新多个对象
/// </summary>
/// <param name="Objects">对象列表</param>
/// <returns>更新修改的数据库记录个数</returns>
public int UpdateObjects(System.Collections.IEnumerable Objects)
{
if (Objects == null)
{
throw new ArgumentNullException("Objects");
}
this.CheckBindInfo(Objects, true);
this.CheckConnetion();
int RecordCount = 0;
using (System.Data.IDbCommand cmd = myConnection.CreateCommand())
{
foreach (object obj in Objects)
{
TableBindInfo table = this.GetBindInfo(obj.GetType());
// 拼凑生成SQL更新语句
System.Collections.ArrayList values = new System.Collections.ArrayList();
System.Text.StringBuilder myStr = new System.Text.StringBuilder();
foreach (FieldBindInfo field in table.Fields)
{
object v = field.Property.GetValue(obj, null);
if (myStr.Length > 0)
{
myStr.Append(" , " + System.Environment.NewLine);
}
myStr.Append(FixFieldName(field.FieldName) + " = ? ");
values.Add(field.ToDataBase(v));
}
myStr.Insert(0, "Update " + FixTableName(table.TableName) + " Set ");
string strSQL = BuildCondition(obj, values);
myStr.Append(" Where " + strSQL);
strSQL = myStr.ToString();
// 设置SQL命令对象，填充参数
cmd.Parameters.Clear();
cmd.CommandText = strSQL;
foreach (object v in values)
{
System.Data.IDbDataParameter p = cmd.CreateParameter();
cmd.Parameters.Add(p);
p.Value = v;
}
RecordCount += cmd.ExecuteNonQuery();
} //foreach
} //using
return(RecordCount);
}
/// <summary>
/// 检查一个对象类型的数据库绑定状态，若检查不通过则抛出异常。
/// </summary>
/// <param name="t">对象类型</param>
/// <param name="CheckKey">是否检查定义了关键字段属性</param>
private void CheckBindInfo(Type t, bool CheckKey)
{
TableBindInfo table = this.GetBindInfo(t);
if (table == null)
{
throw new Exception("类型 " + t.FullName + " 未映射到数据库");
}
if (CheckKey)
{
foreach (FieldBindInfo field in table.Fields)
{
if (field.Attribute.Key)
{
return;
}
}
throw new Exception("类型 " + t.FullName + " 未定义关键字段");
}
}
/// <summary>
/// 从数据读取器中读取数据并填充到一个对象中
/// </summary>
/// <param name="ObjInstance">对象实例</param>
/// <param name="info">数据库绑定信息对象</param>
/// <param name="reader">数据读取器</param>
private int InnerReadValues(object ObjInstance, TableBindInfo info, System.Data.IDataReader reader)
{
// 检查参数
if (ObjInstance == null)
{
throw new ArgumentNullException("ObjectInstance");
}
if (info == null)
{
throw new ArgumentNullException("info");
}
if (reader == null)
{
throw new ArgumentNullException("reader");
}
int FieldCount = 0;
// 依次读取各个属性值
foreach (FieldBindInfo field in info.Fields)
{
// 绑定的属性是只读的
if (field.Property.CanWrite == false)
{
continue;
}
// 没有找到绑定的字段
if (field.FieldIndex < 0)
{
continue;
}
// 读取数据字段值
object v = reader.GetValue(field.FieldIndex);
v = field.FromDataBase(v);
// 设置对象属性值
field.Property.SetValue(ObjInstance, v, null);
FieldCount++;
} //foreach
return(FieldCount);
}
/// <summary>
/// 获得指定类型的数据表映射信息对象
/// </summary>
/// <param name="ObjectType">对象类型</param>
/// <returns>获得的映射信息对象</returns>
/// <remarks>
/// 本函数内部使用了 myBufferedInfos 来缓存信息，提高性能。
/// </remarks>
private TableBindInfo GetBindInfo(Type ObjectType)
{
if (ObjectType == null)
{
throw new ArgumentNullException("OjbectType");
}
// 查找已缓存的映射信息对象
TableBindInfo info = ( TableBindInfo )myBufferedInfos[ObjectType];
if (info != null)
{
return(info);
}
// 若未找到则创建新的映射信息对象
BindTableAttribute ta = ( BindTableAttribute )System.Attribute.GetCustomAttribute(
ObjectType, typeof(BindTableAttribute));
if (ta == null)
{
return(null);
}
TableBindInfo NewInfo = new TableBindInfo();
NewInfo.ObjectType = ObjectType;
NewInfo.Attribute = ta;
NewInfo.TableName = ta.Name;
if (NewInfo.TableName == null || NewInfo.TableName.Trim().Length == 0)
{
// 若在特性中没有指明绑定的表名则使用默认的对象类型名称
NewInfo.TableName = ObjectType.Name;
}
System.Text.StringBuilder myFieldList = new System.Text.StringBuilder();
System.Collections.ArrayList fields = new System.Collections.ArrayList();
// 遍历所有的公开的实例属性来获得字段绑定信息
foreach (System.Reflection.PropertyInfo p in ObjectType.GetProperties(
System.Reflection.BindingFlags.Instance
| System.Reflection.BindingFlags.Public
))
{
BindFieldAttribute fa = ( BindFieldAttribute )Attribute.GetCustomAttribute(
p, typeof(BindFieldAttribute));
if (fa != null)
{
FieldBindInfo NewFieldInfo = new FieldBindInfo();
NewFieldInfo.Attribute = fa;
NewFieldInfo.FieldName = fa.Name;
if (NewFieldInfo.FieldName == null || NewFieldInfo.FieldName.Trim().Length == 0)
{
// 若在特性中没有指明绑定的字段名则使用默认的属性名称
NewFieldInfo.FieldName = p.Name;
}
if (myFieldList.Length > 0)
{
myFieldList.Append(",");
}
myFieldList.Append(FixFieldName(NewFieldInfo.FieldName));
NewFieldInfo.Property = p;
NewFieldInfo.ValueType = p.PropertyType;
NewFieldInfo.DefaultValue = GetDefaultValue(p);
fields.Add(NewFieldInfo);
}
}
NewInfo.Fields = ( FieldBindInfo[])fields.ToArray(typeof(FieldBindInfo));
NewInfo.FieldNameList = myFieldList.ToString();
// 缓存绑定信息对象
myBufferedInfos[ObjectType] = NewInfo;
return(NewInfo);
}
/// <summary>
/// 将若干个对象插入到数据库中
/// </summary>
/// <param name="Objects">对象列表</param>
/// <param name="TableName">制定的数据表，若未指定则使用默认的数据表名</param>
/// <returns>插入的数据库记录的个数</returns>
public int InsertObjects(System.Collections.IEnumerable Objects, string TableName)
{
if (Objects == null)
{
throw new ArgumentNullException("Objects");
}
this.CheckBindInfo(Objects, false);
System.Collections.ArrayList list = new System.Collections.ArrayList();
foreach (object obj in Objects)
{
list.Add(obj);
}
if (list.Count == 0)
{
return(0);
}
this.CheckConnetion();
// 上一次执行的SQL语句
string strLastSQL = null;
int InsertCount = 0;
using (System.Data.IDbCommand cmd = myConnection.CreateCommand())
{
foreach (object obj in list)
{
TableBindInfo table = this.GetBindInfo(obj.GetType());
string TableName2 = TableName;
if (TableName2 == null || TableName.Trim().Length == 0)
{
TableName2 = table.TableName;
}
System.Collections.ArrayList values = new System.Collections.ArrayList();
// 拼凑SQL语句
System.Text.StringBuilder myStr = new System.Text.StringBuilder();
System.Text.StringBuilder myFields = new System.Text.StringBuilder();
foreach (FieldBindInfo field in table.Fields)
{
if (field.Property.CanRead == false)
{
throw new Exception("属性 " + field.Property.Name + " 是不可写的");
}
object v = field.Property.GetValue(obj, null);
if (v == null || DBNull.Value.Equals(v))
{
continue;
}
values.Add(field.ToDataBase(v));
if (myStr.Length > 0)
{
myStr.Append(" , ");
myFields.Append(" , ");
}
myStr.Append(" ? ");
myFields.Append(FixFieldName(field.FieldName));
} //foreach
myStr.Insert(0, "Insert Into " + FixTableName(TableName2)
+ " ( " + myFields.ToString() + " ) Values ( ");
myStr.Append(" ) ");
string strSQL = myStr.ToString();
if (strSQL != strLastSQL)
{
// 重新设置SQL命令对象
strLastSQL = strSQL;
cmd.Parameters.Clear();
cmd.CommandText = strSQL;
for (int iCount = 0; iCount < values.Count; iCount++)
{
cmd.Parameters.Add(cmd.CreateParameter());
}
}
// 填充SQL命令参数值
for (int iCount = 0; iCount < values.Count; iCount++)
{
((System.Data.IDbDataParameter)cmd.Parameters[iCount]).Value = values[iCount];
}
// 执行SQL命令向数据表新增记录
InsertCount += cmd.ExecuteNonQuery();
} //foreach
} //using
return(InsertCount);
}
/// <summary>
/// 使用指定的SQL查询语句查询数据库并读取多条数据库记录对象
/// </summary>
/// <param name="strSQL">SQL查询语句</param>
/// <param name="ObjectType">要读取的对象类型</param>
/// <param name="MaxObjectCount">最多读取的对象个数</param>
/// <returns>读取的对象组成的数组</returns>
public object[] ReadObjects(string strSQL, Type ObjectType, int MaxObjectCount)
{
// 检查参数
if (strSQL == null)
{
throw new ArgumentNullException("strSQL");
}
if (ObjectType == null)
{
throw new ArgumentNullException("ObjectType");
}
// 检查数据库映射信息
this.CheckBindInfo(ObjectType, false);
// 检查数据库连接
this.CheckConnetion();
// 创建SQL命令对象
using (System.Data.IDbCommand cmd = myConnection.CreateCommand())
{
// 执行SQL查询,获得一个数据读取器
cmd.CommandText = strSQL;
System.Data.IDataReader reader = cmd.ExecuteReader(
MaxObjectCount == 1 ?
System.Data.CommandBehavior.SingleRow :
System.Data.CommandBehavior.SingleResult);
System.Collections.ArrayList list = new System.Collections.ArrayList();
TableBindInfo table = this.GetBindInfo(ObjectType);
lock ( table )
{
// 设置字段序号，提高性能
foreach (FieldBindInfo field in table.Fields)
{
field.FieldIndex = -1;
}
for (int iCount = 0; iCount < reader.FieldCount; iCount++)
{
string name = reader.GetName(iCount);
foreach (FieldBindInfo field in table.Fields)
{
if (EqualsFieldName(name, field.FieldName))
{
field.FieldIndex = iCount;
}
}
}
while (reader.Read())
{
// 根据对象类型创建对象实例
object obj = System.Activator.CreateInstance(ObjectType);
// 读取对象属性值
if (InnerReadValues(obj, table, reader) > 0)
{
list.Add(obj);
}
if (MaxObjectCount > 0 || list.Count == MaxObjectCount)
{
break;
}
} //while
} //lock
reader.Close();
// 返回读取的对象数组
return(list.ToArray());
} //using
}
/// <summary>
/// �����ݶ�ȡ���ж�ȡ���ݲ���䵽һ��������
/// </summary>
/// <param name="ObjInstance">����ʵ��</param>
/// <param name="info">���ݿ����Ϣ����</param>
/// <param name="reader">���ݶ�ȡ��</param>
private int InnerReadValues( object ObjInstance , TableBindInfo info , System.Data.IDataReader reader )
{
// ������
if( ObjInstance == null )
{
throw new ArgumentNullException("ObjectInstance");
}
if( info == null )
{
throw new ArgumentNullException("info");
}
if( reader == null )
{
throw new ArgumentNullException("reader");
}
int FieldCount = 0 ;
// ���ζ�ȡ��������ֵ
foreach( FieldBindInfo field in info.Fields )
{
// ��������ֻ����
if( field.Property.CanWrite == false )
{
continue ;
}
// û���ҵ����ֶ�
if( field.FieldIndex < 0 )
{
continue ;
}
// ��ȡ�����ֶ�ֵ
object v = reader.GetValue( field.FieldIndex );
v = field.FromDataBase( v );
// ���ö�������ֵ
field.Property.SetValue( ObjInstance , v , null );
FieldCount ++ ;
}//foreach
return FieldCount ;
}
/// <summary>
/// ���ָ�����͵����ݱ�ӳ����Ϣ����
/// </summary>
/// <param name="ObjectType">��������</param>
/// <returns>��õ�ӳ����Ϣ����</returns>
/// <remarks>
/// �������ڲ�ʹ���� myBufferedInfos ��������Ϣ��������ܡ�
/// </remarks>
private TableBindInfo GetBindInfo( Type ObjectType )
{
if( ObjectType == null )
{
throw new ArgumentNullException("OjbectType");
}
// �����ѻ����ӳ����Ϣ����
TableBindInfo info = ( TableBindInfo ) myBufferedInfos[ ObjectType ] ;
if( info != null )
{
return info ;
}
// ��δ�ҵ����µ�ӳ����Ϣ����
BindTableAttribute ta = ( BindTableAttribute ) System.Attribute.GetCustomAttribute(
ObjectType , typeof( BindTableAttribute ));
if( ta == null )
{
return null;
}
TableBindInfo NewInfo = new TableBindInfo();
NewInfo.ObjectType = ObjectType ;
NewInfo.Attribute = ta ;
NewInfo.TableName = ta.Name ;
if( NewInfo.TableName == null || NewInfo.TableName.Trim().Length == 0 )
{
// ����������û��ָ���ı�����ʹ��Ĭ�ϵĶ�����������
NewInfo.TableName = ObjectType.Name ;
}
System.Text.StringBuilder myFieldList = new System.Text.StringBuilder();
System.Collections.ArrayList fields = new System.Collections.ArrayList();
// �������еĹ�����ʵ������������ֶΰ���Ϣ
foreach( System.Reflection.PropertyInfo p in ObjectType.GetProperties(
System.Reflection.BindingFlags.Instance
| System.Reflection.BindingFlags.Public
))
{
BindFieldAttribute fa = ( BindFieldAttribute ) Attribute.GetCustomAttribute(
p , typeof( BindFieldAttribute ));
if( fa != null )
{
FieldBindInfo NewFieldInfo = new FieldBindInfo();
NewFieldInfo.Attribute = fa ;
NewFieldInfo.FieldName = fa.Name ;
if( NewFieldInfo.FieldName == null || NewFieldInfo.FieldName.Trim().Length == 0 )
{
// ����������û��ָ�����ֶ�����ʹ��Ĭ�ϵ���������
NewFieldInfo.FieldName = p.Name ;
}
if( myFieldList.Length > 0 )
{
myFieldList.Append(",");
}
myFieldList.Append( FixFieldName( NewFieldInfo.FieldName ) ) ;
NewFieldInfo.Property = p ;
NewFieldInfo.ValueType = p.PropertyType ;
NewFieldInfo.DefaultValue = GetDefaultValue( p );
fields.Add( NewFieldInfo );
}
}
NewInfo.Fields = ( FieldBindInfo[]) fields.ToArray( typeof( FieldBindInfo ));
NewInfo.FieldNameList = myFieldList.ToString();
// �������Ϣ����
myBufferedInfos[ ObjectType ] = NewInfo ;
return NewInfo ;
}
