前些时间看了玉开兄的“ 如此高效通用的分页存储过程是带有sql注入漏洞的 ”这篇文章,才突然想起某个项目也是使用了累似的通用分页存储过程。使用这种通用的存储过程进行分页查询,想要防SQL注入,只能对输入的参数进行过滤,例如将一个单引号“'”转换成两个单引号“''”,但这种做法是不安全的,厉害的黑客可以通过编码的方式绕过单引号的过滤,要想有效防SQL注入,只有参数化查询才是最终的解决方案。但问题就出在这种通用分页存储过程是在存储过程内部进行SQL语句拼接,根本无法修改为参数化的查询语句,因此这种通用分页存储过程是不可取的。但是如果不用通用的分页存储过程,则意味着必须为每个具体的分页查询写一个分页存储过程,这会增加不少的工作量。
经过几天的时间考虑之后,想到了一个用代码来生成参数化的通用分页查询语句的解决方案。代码如下:
public class PagerQuery
{
private int _pageIndex;
private int _pageSize = 20 ;
private string _pk;
private string _fromClause;
private string _groupClause;
private string _selectClause;
private string _sortClause;
private StringBuilder _whereClause;
public DateTime DateFilter = DateTime.MinValue;
protected QueryBase()
{
_whereClause = new StringBuilder();
}
/**/ /// <summary>
/// 主键
/// </summary>
public string PK
{
get { return _pk; }
set { _pk = value; }
}
public string SelectClause
{
get { return _selectClause; }
set { _selectClause = value; }
}
public string FromClause
{
get { return _fromClause; }
set { _fromClause = value; }
}
public StringBuilder WhereClause
{
get { return _whereClause; }
set { _whereClause = value; }
}
public string GroupClause
{
get { return _groupClause; }
set { _groupClause = value; }
}
public string SortClause
{
get { return _sortClause; }
set { _sortClause = value; }
}
/**/ /// <summary>
/// 当前页数
/// </summary>
public int PageIndex
{
get { return _pageIndex; }
set { _pageIndex = value; }
}
/**/ /// <summary>
/// 分页大小
/// </summary>
public int PageSize
{
get { return _pageSize; }
set { _pageSize = value; }
}
/**/ /// <summary>
/// 生成缓存Key
/// </summary>
/// <returns></returns>
public override string GetCacheKey()
{
const string keyFormat = " Pager-SC:{0}-FC:{1}-WC:{2}-GC:{3}-SC:{4} " ;
return string .Format(keyFormat, SelectClause, FromClause, WhereClause, GroupClause, SortClause);
}
/**/ /// <summary>
/// 生成查询记录总数的SQL语句
/// </summary>
/// <returns></returns>
public string GenerateCountSql()
{
StringBuilder sb = new StringBuilder();
sb.AppendFormat( " from {0} " , FromClause);
if (WhereClause.Length > 0 )
sb.AppendFormat( " where 1=1 {0} " , WhereClause);
if ( ! string .IsNullOrEmpty(GroupClause))
sb.AppendFormat( " group by {0} " , GroupClause);
return string .Format( " Select count(0) {0} " , sb);
}
/**/ /// <summary>
/// 生成分页查询语句,包含记录总数
/// </summary>
/// <returns></returns>
public string GenerateSqlIncludeTotalRecords()
{
StringBuilder sb = new StringBuilder();
if ( string .IsNullOrEmpty(SelectClause))
SelectClause = " * " ;
if ( string .IsNullOrEmpty(SortClause))
SortClause = PK;
int start_row_num = (PageIndex - 1 ) * PageSize + 1 ;
sb.AppendFormat( " from {0} " , FromClause);
if (WhereClause.Length > 0 )
sb.AppendFormat( " where 1=1 {0} " , WhereClause);
if ( ! string .IsNullOrEmpty(GroupClause))
sb.AppendFormat( " group by {0} " , GroupClause);
string countSql = string .Format( " Select count(0) {0}; " , sb);
string tempSql =
string .Format(
" WITH t AS (SELECT ROW_NUMBER() OVER(ORDER BY {0}) as row_number,{1}{2}) Select * from t where row_number BETWEEN {3} and {4}; " ,
SortClause, SelectClause, sb, start_row_num, (start_row_num + PageSize - 1 ));
return tempSql + countSql;
}
/**/ /// <summary>
/// 生成分页查询语句
/// </summary>
/// <returns></returns>
public override string GenerateSql()
{
StringBuilder sb = new StringBuilder();
if ( string .IsNullOrEmpty(SelectClause))
SelectClause = " * " ;
if ( string .IsNullOrEmpty(SortClause))
SortClause = PK;
int start_row_num = (PageIndex - 1 ) * PageSize + 1 ;
sb.AppendFormat( " from {0} " , FromClause);
if (WhereClause.Length > 0 )
sb.AppendFormat( " where 1=1 {0} " , WhereClause);
if ( ! string .IsNullOrEmpty(GroupClause))
sb.AppendFormat( " group by {0} " , GroupClause);
return
string .Format(
" WITH t AS (SELECT ROW_NUMBER() OVER(ORDER BY {0}) as row_number,{1}{2}) Select * from t where row_number BETWEEN {3} and {4} " ,
SortClause, SelectClause, sb, start_row_num, (start_row_num + PageSize - 1 ));
}
}
使用方法:
PagerQuery query = new PagerQuery();
query.PageIndex = 1;
query.PageSize = 20;
query.PK = "ID";
query.SelectClause = "*";
query.FromClause = "TestTable";
query.SortClause = "ID DESC";
if (!string.IsNullOrEmpty(code))
{
query.WhereClause.Append(" and ID= @ID");
}
a) GenerateCountSql ()方法生成的语句为:
Select count(0) from TestTable Where 1=1 and ID= @ID
b) GenerateSql()方法生成的语句为:
WITH t AS (SELECT ROW_NUMBER() OVER(ORDER BY ECID DESC) as row_number, * from TestTable where 1=1 and ID= @ID) Select * from t where row_number BETWEEN 1 and 20
c) GenerateSqlIncludetTotalRecords()方法生成的语句为:
WITH t AS (SELECT ROW_NUMBER() OVER(ORDER BY E.ECID DESC) as row_number,* from TestTable where 1=1 and ID= @ID) Select * from t where row_number BETWEEN 1 and 20;Select count(0) from ECBasicInfo where 1=1 and ID= @ID;
注意:以上代码生成的SQL语句是曾对SQL SERVER 2005以上版本的,希望这些代码对大家有用
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