/// <summary>
/// 解释 WHERE 子句。
/// </summary>
/// <param name="DbParameters">用于缓存在解释过程中可能会产生的参数。</param>
/// <returns></returns>
public override string Parsing(ref List <IDbDataParameter> DbParameters)
{
WhereBlock wb = (WhereBlock)this.Description;
if (wb.Content == null)
{
return(string.Empty);
}
if (wb.Content.Count < 1)
{
return(string.Empty);
}
StringBuilder cBuffer = new StringBuilder(" WHERE");
IDescription D;
string item_buf;
foreach (object item in wb.Content)
{
if (item is IDescription)
{
D = (IDescription)item;
D.DescriptionParserAdapter = wb.DescriptionParserAdapter;
item_buf = D.GetParser().Parsing(ref DbParameters);
if (item_buf[0] == (char)0x20) // 检查并补空格（与前一元素间没有空格可能会出错。）
{
cBuffer.Append(item_buf);
}
else
{
cBuffer.AppendFormat(" {0}", item_buf);
}
}
else if (item is char)
{
switch ((char)item)
{
case '&':
cBuffer.Append(" AND");
break;
case '|':
cBuffer.Append(" OR");
break;
case '(':
cBuffer.Append(" (");
break;
case ')':
cBuffer.Append(")");
break;
}
}
}
return(cBuffer.ToString());
}
protected SqlSelectBuilderBase(SqlSelectBuilderBase copyFrom)
{
CustomSqlBlocks = copyFrom.CustomSqlBlocks;
FromTablesBlock = copyFrom.FromTablesBlock;
JoinsBlock = copyFrom.JoinsBlock;
OrdersBlock = copyFrom.OrdersBlock;
SelectValuesBlock = copyFrom.SelectValuesBlock;
WhereBlock = copyFrom.WhereBlock;
CurrentPosition = copyFrom.CurrentPosition;
Tables = copyFrom.Tables;
FirstSqlColumns = copyFrom.FirstSqlColumns;
}