public void AddWhere(WhereExpression expression)
{
if (expression == null)
{
return;
}
if (this.Where == null)
{
this.Where = expression;
}
else
{
this.Where = WhereExpression.Create(this.Where, expression, QueryOperator.And);
}
}
public static WhereExpression GetPrimaryKeyWhere(Entity entity)
{
var pkFilds = entity.GetPrimaryKeyFields();
var exp = new WhereExpression();
foreach (var field in pkFilds)
{
var newExp = field == entity.GetValue(field.PropertyName);
if (WhereExpression.IsNullOrEmpty(exp))
{
exp = newExp;
}
else
{
exp = WhereExpression.Create(exp, newExp, QueryOperator.And);
}
}
return(exp);
}
public static WhereExpression GetPrimaryKeyWhere <T>(object[] pkValues)
where T : Entity
{
var entity = EntityHelper.GetTable <T>();
var pkFilds = entity.GetPrimaryKeyFields();
var exp = new WhereExpression();
for (var i = 0; i < pkFilds.Length; i++)
{
var field = pkFilds[i];
var value = pkValues[i];
if (WhereExpression.IsNullOrEmpty(exp))
{
exp = field == value;
}
else
{
exp = WhereExpression.Create(exp, field == value, QueryOperator.Or);
}
}
return(exp);
}
/// <summary>
/// 跳过N行
/// 实现方案： 根据排序和条件检索出全部数据
/// 再加入一个条件：id 大于/或小于(需要根据排序来判断) 前N行记录ID的最大/最小值
/// </summary>
/// <param name="translater"></param>
protected virtual void PrepareSkip(ExpressionTranslater translater)
{
var exp = translater.Expression;
var idField = exp.From.GetIdentityField();
if ((idField as object) == null)
{
throw new NotImplementedException(TextResource.AutoKeyToSearchAllow);
}
var IsIdentityFieldDesc = exp.IsIdentityFieldDesc;
//子查询
var subTableName = "subtable";
var subId = idField.SetTableName(subTableName);
var subTable = DataHelper.Clone(exp.From) as Entity;
subTable.SetAliasName(subTableName);
var subExp = new EntityQueryExpression(subTable);
//前N行记录ID的最大/最小值
if (IsIdentityFieldDesc)
{
subExp.Select = new SelectExpression(new Field[] { subId.Min() });
}
else
{
subExp.Select = new SelectExpression(new Field[] { subId.Max() });
}
//复制条件与排序
subExp.Where = exp.Where.Clone();
subExp.Where.SetTable(subTableName);
subExp.OrderByList = exp.OrderByList.Clone().SetTable(subTableName);
//再加入一个条件：id 大于/或小于(需要根据排序来判断) 前N行记录ID的最大/最小值
var newWhere = WhereExpression.Create(exp.From.GetIdentityField(), subExp,
IsIdentityFieldDesc ? QueryOperator.Less : QueryOperator.Greater);
exp.Where = WhereExpression.Create(exp.Where, newWhere, QueryOperator.And);
}
/// <summary>
/// 翻译查询条件表达式
/// </summary>
/// <param name="exp"></param>
/// <returns></returns>
public string TranslateWhere(WhereExpression exp)
{
StringBuilder str = new StringBuilder();
if (exp.IsSingle)
{
if (exp.Operator == QueryOperator.BitwiseNOT)
{
if (exp.Quote != null && exp.Quote.Operator == QueryOperator.In)
{
return(TranslateWhere(WhereExpression.Create(exp.Quote.LeftField, exp.Quote.Value, QueryOperator.NotIn)));
}
}
if ((exp.LeftField as object) != null && (exp.RightField as object) != null)
{
str.Append(exp.LeftField.FieldNameWithTable);
str.Append(DataHelper.GetOperatorQueryText(exp.Operator));
str.Append(exp.RightField.FieldNameWithTable);
}
else if ((exp.LeftField as object) != null)
{
str.Append(exp.LeftField.FieldNameWithTable);
str.Append(DataHelper.GetOperatorQueryText(exp.Operator));
//子查询 这里只暂时支持写在左边
if (exp.SubExpression != null)
{
str.Append("(" + this.TranslateEntityQuery(exp.SubExpression) + ")");
}
else if (exp.Operator == QueryOperator.In || exp.Operator == QueryOperator.NotIn)
{
str.Append("(");
if (exp.Value != null)
{
var appended = false;
foreach (var value in (IEnumerable)exp.Value)
{
var parm = new QueryParameter(CreateParmName(), value);
this.Params.Add(parm);
if (appended)
{
str.Append(",");
}
str.Append(parm.Name);
appended = true;
}
}
str.Append(")");
}
else if (exp.Operator != QueryOperator.IsNotNULL && exp.Operator != QueryOperator.IsNULL)
{
var parm = new QueryParameter(CreateParmName(), exp.Value);
this.Params.Add(parm);
str.Append(parm.Name);
}
}
else if ((exp.RightField as object) != null)
{
var parm = new QueryParameter(CreateParmName(), exp.Value);
str.Append(parm.Name);
str.Append(DataHelper.GetOperatorQueryText(exp.Operator));
str.Append(exp.RightField.FieldNameWithTable);
this.Params.Add(parm);
}
}
else
{
str.Append("(" + this.TranslateWhere(exp.Left) + ")");
str.Append(DataHelper.GetOperatorQueryText(exp.Operator));
str.Append("(" + this.TranslateWhere(exp.Right) + ")");
}
if (str.Length < 8)
{
return("");
}
return(str.ToString());
}