/// <summary>
/// 删除实体类，如果未指定条件，则使用主键值为条件。
/// </summary>
/// <returns>条件表达式</returns>
public OQL1 Delete()
{
optFlag = "DELETE ";
sqlUpdate = "DELETE FROM [" + this.currEntity.TableName + "] ";
oql1 = new OQL1(this.currEntity, this);
oql1.Selected = true;
return oql1;
}
/// <summary>
/// 更新实体类的某些属性值，如果未指定条件，则使用主键值为条件。
/// </summary>
/// <param name="fields">实体熟悉列表</param>
/// <returns>条件表达式</returns>
public OQL1 Update(params object[] fields)
{
optFlag = "UPDATE ";
sqlUpdate = "UPDATE [" + this.currEntity.TableName + "] SET ";
updateParameters = new Dictionary<string, object>();
foreach (string field in selectedFields)
{
sqlUpdate += "[" + field + "]=@" + field + ",";
updateParameters.Add(field, this.currEntity.PropertyList(field));//某些数据库不支持"@" 格式的参数名称
}
sqlUpdate = sqlUpdate.TrimEnd(',');
oql1 = new OQL1(this.currEntity, this);
oql1.Selected = true;
return oql1;
}
/// <summary>
/// 执行自操作的字段更新，比如为某一个数值性字段执行累加
/// </summary>
/// <param name="selfOptChar">自操作类型，有+，-，*，/ 四种类型</param>
/// <param name="fields">字段列表</param>
/// <returns></returns>
public OQL1 UpdateSelf(char selfOptChar, params object[] fields)
{
if (selfOptChar == '+' || selfOptChar == '-' || selfOptChar == '*' || selfOptChar == '/')
{
optFlag = "UPDATE ";
sqlUpdate = "UPDATE [" + this.currEntity.TableName + "] SET ";
updateParameters = new Dictionary<string, object>();
foreach (string field in selectedFields)
{
sqlUpdate += "[" + field + "]=[" + field + "] " + selfOptChar + " @" + field + ",";
updateParameters.Add(field, this.currEntity.PropertyList(field));//某些数据库不支持"@" 格式的参数名称
}
sqlUpdate = sqlUpdate.TrimEnd(',');
oql1 = new OQL1(this.currEntity, this);
oql1.Selected = true;
return oql1;
}
throw new Exception("OQL的字段自操作只能是+，-，*，/ 四种类型");
}
/// <summary>
/// 选取实体对象的属性
/// </summary>
/// <param name="fields">属性字段列表</param>
/// <returns>实体对象查询基本表达式</returns>
public OQL1 Select(params object[] fields)
{
hasSelected = true;
if (fields.Length == 0)
selectedFields.Clear();
//注意 有可能OQL对象会重复使用，所以下面的事件不能被注销
//this.currEntity.PropertyGetting -= new EventHandler<PropertyGettingEventArgs>(currEntity_PropertyGetting);
oql1 = new OQL1(this.currEntity, this);
oql1.Selected = true;
return oql1;
}