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一个简单的ORM制作(CURD操作类)
- SQL执行类
- CURD操作类
- 其他酱油类
此篇是为上篇文章填坑的，不知道上篇砸过来的砖头够不够，不够的话请大家继续砸。
CURD操作类负责将用户提供的条件转换为SQL语句,并提供给IHelper执行,返回Model集合.
CURD类需要一个接口抽象出公共方法.便于修改和扩展,提供泛型接口。为了简单起见暂时未提供JOIN的实现，可以以数据库视图替代
public interface IDbOper<T> : IDisposable where T : new() { object Insert(T m);//新增MODEL，返回ID，简单起见只做了INT自增 int Update(string str);//批量更新 int Update(T m);//Model更新 int Delete();//删除 ///拼接字符版，需要自己防止注入，特别是Orderby容易被忽视 IDbOper<T> Select(string sl);//选择字段 IDbOper<T> Where(string sl); IDbOper<T> Orderby(string orby); ///Expression版重载，转化为参数方式执行，以参数方式拼接无注入风险
IDbOper<T> Select(Expression<Func<T, object>> sl); IDbOper<T> Where(Expression<Func<T, bool>> sl); ///Dictionary版重载，需要牛顿ＪＳＯＮ帮忙转化，以参数方式拼接无注入风险,此方式用于“等于”等查询方式，不提供大于小于查询 IDbOper<T> Orderby(Dictionary<string, string> dic); IDbOper<T> Where(Dictionary<string, object> dic); /// IDbOper<T> Index(int i); IDbOper<T> Size(int i); T First();//获取第一个model void BegTran(); void RollBack(); void Commit();
M ToObj<M>(Func<IDataReader, M> func,string sql); List<T> ToList(); //转化为其他类型，若开启了事务的话需要此转化 IDbOper<M> ToOper<M>() where M : new(); int Count();
//直接执行SQL语句int DoCommand(string sql, bool issp); }
由于比较喜欢ＪＱ的操作方式，所以想将这种执行方式带到后台操作数据库，废话不说了先定义２个Ｍodel和实例化一个操作类
public class User{ [Key] public int ID{get;set;} public string UserName{get;set;} public string Password{get;set;}}public class NewUser{ [Key] public int ID{get;set;} public string UserName{get;set;} public string Password{get;set;}}
var db=new DbOper<User>(new DbInfo(){DbType="…",DbConntion="…"});
表达式的执行
User a=db.Select(u=>new{u.ID}).Where(u=>u.ID==54).First();
文本拼接的执行
User a=db.Select("*").Where("ID=54").First();
字典拼接的执行
User a=db.Select("*").Where(new Dictionary<string, object>(){Key="ID",Value=http://www.mamicode.com/54}).First();
分页代码
List<User> lt=db.Select("*").Where("ID>0").Orderby("ID Desc").Index(2).Size(20).ToList();
事务的运用
db.BegTran();try{ int b=db.Where("ID=54").Delete();//user表删除ID=54 int c=db.ToOper<NewUser>().Insert(new NewUser(){UserName="…",Password="…"});//newuser表新增一条记录 db.Commit();}catch{db.RollBack();}
只有当调用Insert，Update，Delete，Count，ToList方法才会开始拼接文本再调用IHelper执行SQL语句，调用完成后会自动调用Clear()来清理保存的where，select等信息。
以下是我提供一个操作类的实现，大家也可以实现自己的操作类。
internal class DbOper<T> :IDbPhysiceOper<T>, IDisposable where T : new() { internal IHelper db; internal StringBuilder where; internal StringBuilder select; internal StringBuilder orderby; internal List<IDataParameter> ps; internal StringBuilder sqlinfo; internal int index = 0; internal int size = OrmGlobal.PageSize;//提供一个默认分页大小 private DbOper(IHelper h, StringBuilder w, StringBuilder s, StringBuilder or, List<IDataParameter> p,StringBuilder sql) { db = h; where = w; select = s; orderby = or; sqlinfo = sql; ps = p; } internal DbOper(DbInfo info) { //db为上篇上定义的数据库操作类,分分种切换到其他数据库 if (info.DbType.Equals("mssql")) { db = new Helper.Mssql(info.DbConntion); } else if (info.DbType.Equals("msmars")) { db = new Helper.MsMars(info.DbConntion); } else if (info.DbType.Equals("mysql")) { db = new Helper.Mysql(info.DbConntion); } where = new StringBuilder(); select = new StringBuilder(); orderby = new StringBuilder(); sqlinfo = new StringBuilder(); ps = new List<IDataParameter>(); } public object Insert(T m) { try { StringBuilder fields = new StringBuilder(); StringBuilder values = new StringBuilder(); List<IDataParameter> lt = new List<IDataParameter>(); string tp = string.Empty; object o = null; foreach (var n in m.GetType().GetProperties()) { if (n.GetCustomAttributes(typeof(ExcludeColumn), false).Length > 0) { continue; } if (n.GetCustomAttributes(typeof(Key), false).Length > 0) { continue; } o = n.GetValue(m,null);//4.5o = n.GetValue(m); if (o == null) { continue; } fields.Append(n.Name + ","); tp = db.ParStr(n.Name); values.Append(tp + ","); lt.Add(db.Cp(tp, o)); } if (fields.Length > 0) { fields.Length--; } if (values.Length > 0) { values.Length--; } tp = "INSERT INTO " + typeof(T).Name + "(" + fields.ToString() + ")VALUES(" + values.ToString() + ") " + db.GetIdStr; if (OrmGlobal.isrecord) { Record(tp); } object a = db.ExectueScalar(tp, lt, false); Clear(); return a; } catch { OrmGlobal.DoErr(sqlinfo.ToString()); throw; } } public int Update(string str) { try { string tp = "UPDATE " + typeof(T).Name + " SET " + str + (where.Length > 0 ? " WHERE " + where : string.Empty); if (OrmGlobal.isrecord) { Record(tp); } int i = db.ExecuteQuery(tp, ps, false); Clear(); return i; } catch { OrmGlobal.DoErr(sqlinfo.ToString()); throw; } } public int Update(T m) { try { StringBuilder sb = new StringBuilder(); sb.Append("UPDATE " + typeof(T).Name + " SET "); List<IDataParameter> lt = new List<IDataParameter>(); object o = null; foreach (var n in m.GetType().GetProperties()) {//需要定义一个特性Key,以便更新Model o = n.GetValue(m,null);//4.5o = n.GetValue(m); if (o == null) { continue; } if (n.GetCustomAttributes(typeof(Key), false).Length > 0) { where.Append((where.Length > 0 ? " AND " : string.Empty) + n.Name + "=" + db.ParStr(n.Name)); lt.Add(db.Cp(db.ParStr(n.Name), o)); continue; } sb.Append(n.Name + "=" + db.ParStr(n.Name) + ","); lt.Add(db.Cp(db.ParStr(n.Name), o)); } if (sb.Length > 0) { sb.Length--; } if (where.Length > 0) { sb.Append(" WHERE " + where); } var sql = sb.ToString(); if (OrmGlobal.isrecord) { Record(sql); } int i = db.ExecuteQuery(sql, lt, false); Clear(); return i; } catch { OrmGlobal.DoErr(sqlinfo.ToString()); throw; } } public int Delete() { try { string sql = "DELETE FROM " + typeof(T).Name + (where.Length > 0 ? " WHERE " + where : string.Empty); if (OrmGlobal.isrecord) { Record(sql); } int i = db.ExecuteQuery(sql, ps, false); Clear(); return i; } catch { OrmGlobal.DoErr(sqlinfo.ToString()); throw; } } public IDbOper<T> Select(string sl) { if (string.IsNullOrEmpty(sl)) { return this; } select.Append((select.Length > 0 ? "," : string.Empty) + sl); return this; } public IDbOper<T> Select(Expression<Func<T, object>> sl) { string tp=null; using (var tp1 = new LinqVisitor()) { tp=tp1.VisitNew(sl.Body as NewExpression); } return Select(tp); } public IDbOper<T> Where(Dictionary<string, object> dic) { if (dic == null || dic.Count == 0) { return this; } var sb = new StringBuilder(); string tp; foreach (var n in dic) { if (sb.Length > 0) { sb.Append(" AND "); } sb.Append(n.Key); if (n.Value is string) { tp = n.Value.ToString(); if (tp.Substring(tp.Length - 1, 1) == "*") { sb.Append(" LIKE "); tp = tp.Substring(0, tp.Length - 1) + "%"; } else { sb.Append("="); } ps.Add(db.Cp(db.ParStr(n.Key), tp)); } else { sb.Append("="); ps.Add(db.Cp(db.ParStr(n.Key), n.Value)); } sb.Append(db.ParStr(n.Key)); } Where(sb.ToString()); return this; } public IDbOper<T> Where(string sl) { if (string.IsNullOrEmpty(sl)) { return this; } where.Append((where.Length > 0 ? " AND " : string.Empty) + sl); return this; } public IDbOper<T> Where(Expression<Func<T, bool>> sl) { List<object> tp=null; //需要解析表达式树 using (var tp1 = new LinqVisitor()) { tp = tp1.Visit(sl) as List<object>; StringBuilder sb = new StringBuilder(); string s = string.Empty; for (int i = 0; i < tp.Count; i += 4) { s = db.ParStr(tp[i].ToString()); sb.Append(tp[i].ToString() + tp[i + 1].ToString() + s); if (i + 4 < tp.Count) { sb.Append(tp[i + 3]); } ps.Add(db.Cp(s, tp[i + 2])); } Where(sb.ToString()); } return this; } public IDbOper<T> Orderby(string orby) { if (string.IsNullOrEmpty(orby)) { return this; } orderby.Append((orderby.Length > 0 ? "," : string.Empty) + orby); return this; } public IDbOper<T> Orderby(Dictionary<string, string> dic) { if (dic.Count == 0) { return this; } StringBuilder sb = new StringBuilder(); foreach (var n in dic.Keys) { if(string.Compare("DESC",dic[n],true)!=0 && string.Compare("ASC",dic[n],true)!=0){continue;} sb.Append(n + " " + dic[n] + ","); } if (sb.Length > 0) { sb.Length--; } Orderby(sb.ToString()); return this; } public IDbOper<T> Index(int i) { if (i > 0) { index = i; } return this; } public IDbOper<T> Size(int i) { if (i > 0) { size = i; } return this; } public void BegTran() { db.BegTran(); } public void RollBack() { db.RollBack(); } public void Commit() { db.Commit(); } public void Clear() { where.Length = 0; select.Length = 0; orderby.Length = 0; ps.Clear(); index = 0; size = OrmGlobal.size; } public M ToObj<M>(Func<IDataReader, M> func, string sql) { try { if (OrmGlobal.isrecord) { Record(sql); } var rd = db.ExectueReader(sql, ps, false); M t = func(rd); rd.Close(); Clear(); return t; } catch { OrmGlobal.DoErr(sqlinfo.ToString()); throw; } } public List<T> ToList() { string sql = GetSql(); return ToObj<List<T>>(rd => ToList(rd),sql); } //返回List<T>类型 public List<T> ToList(IDataReader rd) { var lt = new List<T>(); var set = DelegateExpr.SetMethod(typeof(T));//ExpressTree实现属性绑定,以提高Model赋值性能，可以以反射代替 while (rd.Read()) { var m = new T(); for (var i = 0; i < rd.FieldCount; i++) { if (rd[i] == DBNull.Value || rd[i] == null) { continue; } set(m, rd.GetName(i).ToLower(), rd[i]); } lt.Add(m); } return lt; } public string GetSql() { return db.CreateSql(select.ToString(), typeof(T).Name, where.ToString(), orderby.ToString(), size, index); } public IDbOper<M> ToOper<M>() where M:new() { Clear(); return new DbOper<M>(db,where,select,orderby,ps,sqlinfo); } public int Count() { try { string sql = "SELECT COUNT(*) FROM " + typeof(T).Name + (where.Length > 0 ? " WHERE " + where : string.Empty); if (OrmGlobal.RecordLog) { Record(sql); } int i= (int)db.ExectueScalar(sql, ps, false); Clear(); return i; } catch { OrmGlobal.DoErr(sqlinfo.ToString()); throw; } } public int DoCommand(string sql,bool issp) { int i=db.ExecuteQuery(sql,ps,issp); Clear(); return i; } public void Dispose() { where = null; select = null; orderby = null; db.Dispose(); ps = null; sqlinfo = null; GC.SuppressFinalize(this); } public T First() { var lt=Size(1).Index(1).ToList(); if (lt.Count > 0) { return lt[0]; } return default(T); } ~DbOper() { Dispose(); } }
一个简单的ORM制作(CURD操作类)
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