C#中一套生成sql条件的类

最新推荐文章于 2021-11-20 23:56:58 发布

FreeEasy10

最新推荐文章于 2021-11-20 23:56:58 发布

阅读量827

点赞数

文章标签： sql c# string null object float

本文介绍了一个用于简化SQL查询条件生成的小工具类。该工具通过Condition类及两个枚举类型，帮助开发者快速构造复杂的SQL查询条件，提高了代码的可读性和可维护性。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

在进行sql查询的时候，有时候要进行很多条件限制，自己来拼写SQLwhere条件容易出错，而且判断条件复杂，后期维护困难，基于这个原因我在一个小项目中写了一套生成sql条件的类。总共包括一个Condition类，与两个枚举型类型（LogicOper，CompareOper）代码如下： public class Condition { static string [] logicOpers = new string[]{"and","or"}; static string [] compareOpers = new string[]{">","<","<=",">=","=","<>","like","not like","in"}; string compareOper=null; string name=null; string templateName = null; string valType=null; object val=null; public Condition(CompareOper co,string valType,string name,object val) { this.compareOper = compareOpers[(int)co]; this.name = name; templateName = name; this.valType = valType; this.val = val; } public Condition(CompareOper co,string valType,string name,object val,string templateName) { this.compareOper = compareOpers[(int)co]; this.name = name; this.templateName = templateName; this.valType = valType; this.val = val; } public Condition(){} public string toSqlString() { string [] arr1 = (string[])operaters.ToArray("".GetType()); Condition [] arr2 = (Condition[])conditions.ToArray((new Condition()).GetType()); StringBuilder outStr = new StringBuilder(); int count=0; if(name!=null&&val!=null) { outStr.Append(name); outStr.Append(" "); outStr.Append(compareOper); outStr.Append(" "); if(valType.ToLower()=="int" ||valType.ToLower()=="float" ||valType.ToLower()=="double" ||valType.ToLower()=="bool" ||valType.ToLower()=="number" ) { outStr.Append(val); } else if(valType.ToLower()=="string") { string tmp = (string)val; outStr.Append("’"+tmp.Replace("’","’’")+"’"); } else if(valType.ToLower()=="date") { DateTime dt = (DateTime)val; outStr.Append("’"+dt.ToString("yyyy-MM-dd")+"’"); } else if(valType.ToLower()=="datetime") { DateTime dt = (DateTime)val; outStr.Append("’"+dt.ToString("yyyy-MM-dd hh:mm:ss.fff")+"’"); } else { string tmp = val.ToString(); outStr.Append("’"+tmp.Replace("’","’’")+"’"); } count++; } if(arr1.Length>0) { for(int i=0;i1) { outStr.Append(" "); outStr.Append(arr1[i]); outStr.Append(" "); } outStr.Append(arr2[i].toSqlString()); } } if(count>1) { outStr.Insert(0,’(’); outStr.Append(’)’); } return outStr.ToString(); } public string toSqlTempletString() { string [] arr1 = (string[])operaters.ToArray("".GetType()); Condition [] arr2 = (Condition[])conditions.ToArray((new Condition()).GetType()); StringBuilder outStr = new StringBuilder(); int count=0; if(name!=null&&val!=null) { outStr.Append(name); outStr.Append(" "); outStr.Append(compareOper); outStr.Append(" @"); outStr.Append(templateName); count++; } if(arr1.Length>0) { for(int i=0;i1) { outStr.Append(" "); outStr.Append(arr1[i]); outStr.Append(" "); } outStr.Append(arr2[i].toSqlTempletString()); } } if(count>1) { outStr.Insert(0,’(’); outStr.Append(’)’); } return outStr.ToString(); } public SqlParameter [] getSqlParameters() { ArrayList tmp = new ArrayList(); if(name!=null&&val!=null) { tmp.Add(new SqlParameter("@"+templateName,val)); } Condition [] arr = (Condition[])conditions.ToArray((new Condition()).GetType()); for(int i=0;i