自己写的访问SqlServer数据库的通用DAL层
如题,直接贴代码.
首先是DataTable转List<T>的方法,这个方法通用性极强.
1 #region Table转List 2 /// <summary> 3 /// Table转List 4 /// </summary> 5 /// <typeparam name="T"></typeparam> 6 /// <param name="dt"></param> 7 /// <returns></returns> 8 public static List<T> TableToList<T>(DataTable dt) where T : new() 9 { 10 // 定义集合 11 IList<T> list = new List<T>(); 12 13 // 获得此模型的类型 14 Type type = typeof(T); 15 16 foreach (DataRow dr in dt.Rows) 17 { 18 T t = new T(); 19 20 // 获得公共属性 21 PropertyInfo[] propertys = t.GetType().GetProperties(); 22 23 foreach (PropertyInfo pi in propertys) 24 { 25 // 判断此属性是否有Setter 26 if (!pi.CanWrite) continue; 27 28 object value = dr[pi.Name]; 29 if (value != DBNull.Value) 30 pi.SetValue(t, value, null); 31 } 32 33 list.Add(t); 34 } 35 return list.ToList(); 36 } 37 #endregion
下面贴出主要代码
1 /// <summary> 2 /// 数据访问基类:BaseService 3 /// </summary> 4 /// <typeparam name="T"></typeparam> 5 public class BaseService<T> : IBaseService<T> where T : class ,new() 6 { 7 /// <summary> 8 /// 得到某列最大值 9 /// </summary> 10 /// <param name="connection"></param> 11 /// <param name="fieldname"></param> 12 /// <returns></returns> 13 public virtual int GetMax(string connection,string fieldname) 14 { 15 #region 参数 16 T entity = new T(); 17 SqlParameter[] parameters = new SqlParameter[] 18 { 19 new SqlParameter("@fieldname",fieldname) 20 }; 21 #endregion 22 23 StringBuilder sqlStr=new StringBuilder(); 24 sqlStr.Append("select max("); 25 sqlStr.Append("@fieldname"); 26 sqlStr.Append(") from "); 27 sqlStr.Append(entity.GetType().Name); 28 29 return int.Parse(DatabaseAccess.SqlHelper.ExecuteDataSetText(connection, sqlStr.ToString(), parameters).Tables[0].Rows[0][0].ToString()); 30 } 31 32 /// <summary> 33 /// 是否存在该记录 34 /// </summary> 35 /// <param name="connection">连接字符串</param> 36 /// <param name="primarykey">主键值</param> 37 /// <returns></returns> 38 public virtual bool Exists(string connection, object primarykey) 39 { 40 #region 参数 41 T entity = new T(); 42 43 string primaryKey = GetPrimarykey(connection, entity); 44 List<SqlParameter> parameters = new List<SqlParameter>(); 45 parameters.Add(new SqlParameter("@" + primaryKey, primarykey)); 46 #endregion 47 48 StringBuilder sqlStr = new StringBuilder(); 49 sqlStr.Append("select count(1) from "); 50 sqlStr.Append(entity.GetType().Name); 51 sqlStr.Append(" where "); 52 sqlStr.Append(primaryKey + "=@" + primaryKey); 53 54 int res = DatabaseAccess.SqlHelper.ExecteNonQueryText(connection, sqlStr.ToString(), parameters.ToArray()); 55 if (res > 0) 56 return true; 57 else 58 return false; 59 } 60 61 /// <summary> 62 /// 增加一条数据 63 /// </summary> 64 public virtual bool Add(string connection, T entity) 65 { 66 #region 参数 67 List<SqlParameter> parameters = new List<SqlParameter>(); 68 string fields = ""; 69 string placeholders = ""; 70 foreach (var item in entity.GetType().GetProperties()) 71 { 72 fields += item.Name + ","; 73 placeholders += "@" + item.Name + ","; 74 75 SqlParameter parameter = new SqlParameter(); 76 parameter.ParameterName = "@" + item.Name; 77 parameter.Value = item.GetValue(entity, null); 78 parameters.Add(parameter); 79 } 80 #endregion 81 82 StringBuilder sqlStr = new StringBuilder(); 83 sqlStr.Append("insert " + entity.GetType().Name + " ("); 84 sqlStr.Append(fields.Substring(0, fields.Length - 1) + ")"); 85 sqlStr.Append(" values ("); 86 sqlStr.Append(placeholders.Substring(0, placeholders.Length - 1) + ")"); 87 88 int res = DatabaseAccess.SqlHelper.ExecteNonQueryText(connection, sqlStr.ToString(), parameters.ToArray()); 89 if (res > 0) 90 return true; 91 else 92 return false; 93 } 94 95 /// <summary> 96 /// 更新一条数据 97 /// </summary> 98 /// <param name="connection">连接字符串</param> 99 /// <param name="entity">类</param> 100 /// <returns></returns> 101 public virtual bool Update(string connection, T entity) 102 { 103 #region 参数 104 string primaryKey = GetPrimarykey(connection, entity); 105 List<SqlParameter> parameters = new List<SqlParameter>(); 106 parameters.Add(new SqlParameter("@"+primaryKey, entity.GetType().GetProperty(primaryKey).GetValue(entity,null))); 107 string fields = ""; 108 foreach (var item in entity.GetType().GetProperties()) 109 { 110 if (item.Name != primaryKey) 111 { 112 fields += item.Name + "=@" + item.Name + ","; 113 114 SqlParameter parameter = new SqlParameter(); 115 parameter.ParameterName = "@" + item.Name; 116 parameter.Value = item.GetValue(entity, null); 117 parameters.Add(parameter); 118 } 119 } 120 #endregion 121 122 StringBuilder sqlStr = new StringBuilder(); 123 sqlStr.Append("update " + entity.GetType().Name); 124 sqlStr.Append(" set "); 125 sqlStr.Append(fields.Substring(0,fields.Length-1)); 126 sqlStr.Append(" where "); 127 sqlStr.Append(primaryKey + "=@" + primaryKey); 128 129 int res = DatabaseAccess.SqlHelper.ExecteNonQueryText(connection, sqlStr.ToString(), parameters.ToArray()); 130 if (res > 0) 131 return true; 132 else 133 return false; 134 } 135 136 /// <summary> 137 /// 删除一条数据 138 /// </summary> 139 /// <param name="connection">连接字符串</param> 140 /// <param name="primaryKey">主键值</param> 141 /// <returns></returns> 142 public virtual bool Delete(string connection, object primarykey) 143 { 144 #region 参数 145 T entity = new T(); 146 147 string primaryKey = GetPrimarykey(connection, entity); 148 List<SqlParameter> parameters = new List<SqlParameter>(); 149 parameters.Add(new SqlParameter("@" + primaryKey, primarykey)); 150 #endregion 151 152 StringBuilder sqlStr = new StringBuilder(); 153 sqlStr.Append("delete from "); 154 sqlStr.Append(entity.GetType().Name); 155 sqlStr.Append(" where "); 156 sqlStr.Append(primaryKey + "=@" + primaryKey); 157 158 int res = DatabaseAccess.SqlHelper.ExecteNonQueryText(connection, sqlStr.ToString(), parameters.ToArray()); 159 if (res > 0) 160 return true; 161 else 162 return false; 163 } 164 165 /// <summary> 166 /// 删除多条数据 167 /// </summary> 168 /// <param name="connection">连接字符串</param> 169 /// <param name="base_idlist">主键值列表</param> 170 /// <returns></returns> 171 public virtual bool DeleteList(string connection, List<object> primarykeys) 172 { 173 #region 参数 174 T entity = new T(); 175 176 string primaryKey = GetPrimarykey(connection, entity); 177 178 string primaryKeys = ""; 179 foreach(var item in primarykeys) 180 { 181 primaryKeys += item.ToString(); 182 } 183 184 List<SqlParameter> parameters = new List<SqlParameter>(); 185 parameters.Add(new SqlParameter("@" + primaryKey, primaryKeys)); 186 #endregion 187 188 StringBuilder sqlStr = new StringBuilder(); 189 sqlStr.Append("delete from "); 190 sqlStr.Append(entity.GetType().Name); 191 sqlStr.Append(" where "); 192 sqlStr.Append(primaryKey + " in(@" + primaryKey + ")"); 193 194 int res = DatabaseAccess.SqlHelper.ExecteNonQueryText(connection, sqlStr.ToString(), parameters.ToArray()); 195 if (res > 0) 196 return true; 197 else 198 return false; 199 } 200 201 /// <summary> 202 /// 得到一个对象实体 203 /// </summary> 204 /// <param name="connection">连接字符串</param> 205 /// <param name="primarykey">主键值</param> 206 /// <returns></returns> 207 public virtual T GetModel(string connection, object primarykey) 208 { 209 #region 参数 210 T entity = new T(); 211 212 string primaryKey = GetPrimarykey(connection, entity); 213 214 List<SqlParameter> parameters = new List<SqlParameter>(); 215 parameters.Add(new SqlParameter("@table", entity.GetType().Name)); 216 parameters.Add(new SqlParameter("@" + primaryKey, primarykey)); 217 #endregion 218 219 StringBuilder sqlStr = new StringBuilder(); 220 sqlStr.Append("select * from "); 221 sqlStr.Append(entity.GetType().Name); 222 sqlStr.Append(" where "); 223 sqlStr.Append(primaryKey + "=@" + primaryKey); 224 225 return Common.ToList.TableToList<T>(DatabaseAccess.SqlHelper.ExecuteDataSetText(connection, sqlStr.ToString(), parameters.ToArray()).Tables[0]).FirstOrDefault(); 226 } 227 228 /// <summary> 229 /// 获得数据列表 230 /// </summary> 231 /// <param name="connection">连接字符串</param> 232 /// <param name="strWhere">查询条件</param> 233 /// <returns></returns> 234 public virtual List<T> GetList(string connection, string strWhere) 235 { 236 #region 参数 237 T entity = new T(); 238 239 List<SqlParameter> parameters = new List<SqlParameter>(); 240 parameters.Add(new SqlParameter("@where", strWhere)); 241 #endregion 242 243 StringBuilder sqlStr = new StringBuilder(); 244 sqlStr.Append("select * from "); 245 sqlStr.Append(entity.GetType().Name); 246 if (strWhere.Trim().Length > 0) 247 sqlStr.Append(" where @where"); 248 249 return Common.ToList.TableToList<T>(DatabaseAccess.SqlHelper.ExecuteDataSetText(connection, sqlStr.ToString(), parameters.ToArray()).Tables[0]); 250 } 251 252 /// <summary> 253 /// 获得总数 254 /// </summary> 255 /// <param name="connection">连接字符串</param> 256 /// <param name="strWhere">查询条件</param> 257 /// <returns></returns> 258 public virtual int GetRecordCount(string connection, string strWhere) 259 { 260 #region 参数 261 T entity = new T(); 262 263 List<SqlParameter> parameters = new List<SqlParameter>(); 264 parameters.Add(new SqlParameter("@where", strWhere)); 265 #endregion 266 267 StringBuilder sqlStr = new StringBuilder(); 268 sqlStr.Append("select count(1) FROM "); 269 sqlStr.Append(entity.GetType().Name); 270 if (strWhere.Trim().Length > 0) 271 sqlStr.Append(" where @where"); 272 273 return int.Parse(DatabaseAccess.SqlHelper.ExecuteScalarText(connection, sqlStr.ToString(), parameters.ToArray()).ToString()); 274 } 275 276 /// <summary> 277 /// 执行sql语句 278 /// </summary> 279 /// <param name="connection"></param> 280 /// <param name="cmdtype"></param> 281 /// <param name="sql"></param> 282 /// <param name="parameters"></param> 283 /// <returns></returns> 284 public virtual int ExecteNonQuerySQL(string connection, CommandType cmdtype, string sql, params SqlParameter[] parameters) 285 { 286 return DatabaseAccess.SqlHelper.ExecteNonQuery(connection, cmdtype, sql, parameters); 287 } 288 289 /// <summary> 290 /// 获取类主键 291 /// </summary> 292 /// <param name="connection">连接字符串</param> 293 /// <param name="entity">类</param> 294 /// <returns></returns> 295 public virtual string GetPrimarykey(string connection, T entity) 296 { 297 StringBuilder sqlStr = new StringBuilder(); 298 sqlStr.Append("EXEC sp_pkeys @table_name='" + entity.GetType().Name + "'"); 299 300 SqlParameter[] parameters = new SqlParameter[] 301 { 302 303 }; 304 305 return DatabaseAccess.SqlHelper.ExecuteDataSetText(connection,sqlStr.ToString(),parameters).Tables[0].Rows[0]["COLUMN_NAME"].ToString(); 306 } 307 308 /// <summary> 309 /// 执行sql语句 310 /// </summary> 311 /// <param name="connection"></param> 312 /// <param name="cmdtype"></param> 313 /// <param name="sql"></param> 314 /// <param name="parameters"></param> 315 /// <returns></returns> 316 public virtual DataSet ExecuteDataSetSQL(string connection, CommandType cmdtype, string sql, params SqlParameter[] parameters) 317 { 318 return DatabaseAccess.SqlHelper.ExecuteDataSet(connection, cmdtype, sql, parameters); 319 } 320 }
这些方法中默认表都是有主键的,而且实体名称和表名一致,否则执行会报错.
这套方法已经被我用在一个旧项目的改造中,目前来看效果还是不错的,因此在这与大家分享,因为本人水平有限,而且没用太多时间去完善,这套代码肯定会有很多瑕疵,希望高手不吝赐教.