数据库接口基础类 oracle，sql server

1.为数据库读取基类

 public class DBBase : IDisposable
    {
        public virtual void Dispose()
        {
            throw new NotImplementedException();
        }

        public virtual int ExecuteSQL(string sql)
        {
            return 0;
        }

        public virtual DataTable DBGetDataTable(string sql)
        {
            return null;
        }
/// </summary>
        /// <param name="item"></param>
        /// <param name="keyname"></param>
        /// <param name="keyid"></param>
        /// <returns></returns>
        public int ExecuteSQL_Update(object item, string key, string keyvalue)
        {
            if (item == null)
                return -1;
            var type = item.GetType();
            var tablename = type.Name;
            var atts = type.GetProperties();
            string valueset = "";
            foreach (var a in atts)
            {
                var aname = a.Name;
                var value = a.GetValue(item);
                valueset += aname + "=" + GetValue2String(value) + ",";
            }
            valueset = valueset.Trim(',');

            var sql = "UPDATE " + tablename + " set " + valueset + " where " + key + "= '" + keyvalue + "'";
            return ExecuteSQL(sql);
        }


        public int ExecuteSQL_Insert(object item)
        {
            if (item == null)
                return -1;
            var type = item.GetType();
            var tablename = type.Name;
            var atts = type.GetProperties();
            var keys = "";
            var values = "";
            foreach (var a in atts)
            {
                var aname = a.Name;
                var value = a.GetValue(item);
                keys += aname + ",";
                values += GetValue2String(value) + ",";
            }

            keys = keys.Trim(',');
            values = values.Trim(',');

            var sql = "INSERT INTO " + tablename + " ( " + keys + " ) VALUES ( " + values + " )";
            return ExecuteSQL(sql);
        }

        /// <summary>
        /// 获取对象列表
        /// </summary>
        /// <typeparam name="T">表所对应的对象名称</typeparam>
        /// <param name="sql">查询语句</param>
        /// <returns>返回获取到的对象实例列表</returns>
        public List<T> QueryObjectList<T>(string sql) where T : new()
        {
            var table = DBGetDataTable(sql);
            return ConvertTableToObject<T>(table);
        }

        public List<T> ConvertTableToObject<T>(DataTable t) where T : new()
        {
            if (t == null)
                return null;
            List<T> list = new List<T>();
            foreach (DataRow row in t.Rows)
            {
                T obj = new T();
                GetObject(t.Columns, row, obj);
                if (obj != null && obj is T)
                    list.Add(obj);
            }
            return list;
        }

        public T ConvertToObject<T>(DataRow row) where T : new()
        {
            object obj = new T();
            if (row != null)
            {
                DataTable t = row.Table;
                GetObject(t.Columns, row, obj);
            }
            if (obj != null && obj is T)
                return (T)obj;
            else
                return default(T);
        }

        /// <summary>
        /// 获取第一条数据中的某个值
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="key"></param>
        /// <returns></returns>
        public string QueryString(string sql, string key)
        {
            var table = DBGetDataTable(sql);
            if (table != null)
            {
                if (table.Rows.Count >= 1)
                {
                    var row = table.Rows[0];
                    if (row != null)
                    {
                        return GetValue2String(row[key]);
                    }
                }
            }
            return null;
        }

        protected void GetObject(DataColumnCollection cols, DataRow dr, Object obj)
        {
            Type t = obj.GetType();
            var props = t.GetProperties();
            foreach (var pro in props)
            {
                if (cols.Contains(pro.Name))
                {
                    if (dr[pro.Name] != DBNull.Value)
                    {
                        try
                        {
                            switch (pro.PropertyType.Name)
                            {
                                case "Int32":
                                    {
                                        Int32 value = Convert.ToInt32(dr[pro.Name]);
                                        pro.SetValue(obj, value, null);
                                    }
                                    break;

                                case "System.Nullable`1[System.Int32]":
                                    {
                                        Int32 value = Convert.ToInt32(dr[pro.Name]);
                                        pro.SetValue(obj, value, null);
                                    }
                                    break;
                                case "Nullable`1"://数据库可为空的字段处理
                                    {
                                        var name = pro.ToString();
                                        if (name.Contains("System.Nullable`1[System.Int32]"))
                                        {
                                            var intvalue = dr[pro.Name];
                                            if (intvalue != null)
                                            {
                                                Int32 value = Convert.ToInt32(intvalue);
                                                pro.SetValue(obj, value, null);
                                            }
                                        }
                                        else if (name.Contains("System.Nullable`1[System.DateTime]"))
                                        {
                                            var intvalue = dr[pro.Name];
                                            if (intvalue != null)
                                            {
                                                var value = Convert.ToDateTime(intvalue);
                                                pro.SetValue(obj, value, null);
                                            }
                                        }
                                    }
                                    break;
                                case "Double":
                                    {
                                        double value = Convert.ToDouble(dr[pro.Name]);
                                        pro.SetValue(obj, value, null);
                                    }
                                    break;
                                case "Single":
                                    {
                                        float value = Convert.ToSingle(dr[pro.Name]);
                                        pro.SetValue(obj, value, null);
                                    }
                                    break;
                                case "Int64":
                                    {
                                        Int64 value = Convert.ToInt64(dr[pro.Name]);
                                        pro.SetValue(obj, value, null);
                                    }
                                    break;
                                case "Int16":
                                    {
                                        Int16 value = Convert.ToInt16(dr[pro.Name]);
                                        pro.SetValue(obj, value, null);
                                    }
                                    break;
                                case "Decimal":
                                    {
                                        Decimal value = Convert.ToDecimal(dr[pro.Name]);
                                        pro.SetValue(obj, value, null);
                                    }
                                    break;
                                case "String":
                                    {
                                        try
                                        {
                                            var oldt = dr[pro.Name].GetType();

                                            if (oldt.Name  !="String")//这里处理类型不对应的情况，默认model类型是string的时候判断，不对应就转成string，便于model定义
                                            {
                                                pro.SetValue(obj, dr[pro.Name].ToString(), null);
                                            }
                                            else
                                            {
                                                pro.SetValue(obj, dr[pro.Name], null);
                                            }
                                        }
                                        catch
                                        {
                                            pro.SetValue(obj, dr[pro.Name].ToString(), null);
                                        }
                                    }
                                    break;
                                default:
                                    {
                                        pro.SetValue(obj, dr[pro.Name], null);
                                    }
                                    break;
                            }
                        }
                        catch
                        {
                            pro.SetValue(obj, null, null);
                        }
                        finally
                        {
                        }
                    }
                    else
                    {
                        pro.SetValue(obj, null, null);
                    }
                }
            }
        }

        protected string GetValue2String(Object obj)
        {
            if (obj == null)
                return "null";
            Type t = obj.GetType();
            try
            {
                switch (t.Name)
                {
                    case "String":
                        {
                            return "'" + obj.ToString() + "'";
                        }
                    case "DateTime":
                        {
                            return "to_date('" + obj.ToString() + "','YYYY-MM-DD hh24:mi:ss')";//默认获取到的日期格式，可以根据具体需求改
                        }
                    default:
                        {
                            return obj.ToString();
                        }
                }
            }
            catch
            {
                return "";
            }
        }
    }

2.oracle 派生

    public class DBSupport : DBBase
    {
        //public  static string conncet = System.Configuration.ConfigurationManager.AppSettings["conn"].ToString();

        string conn;
        public DBSupport(string connect)
        {
            conn = connect;
            if (mQracleConnecting == null)
                mQracleConnecting = new OracleConnection(connect);
            if (mQracleConnecting.State != ConnectionState.Open)
                mQracleConnecting.Open();
        }

        #region DB
         OracleConnection mQracleConnecting = null;
        public  OracleConnection QracleConnecting
        {
            get
            {
                  return mQracleConnecting;   
            }
        }

        public override  DataTable DBGetDataTable(string sql)
        {
            try
            {
                DataTable dataSet = new DataTable();
                OracleDataAdapter OraDA = new OracleDataAdapter(sql, mQracleConnecting);
                OraDA.Fill(dataSet);
                return dataSet;
            }
            catch (Exception)
            {
                FileSupport.Instance.Write("数据库连接异常" + conn);
                return null;
            }

        }

        // 执行SQL语句,返回所影响的行数   
        public override  int ExecuteSQL(string sql)
        {
            int Cmd = 0;
            OracleCommand command = new OracleCommand(sql, QracleConnecting);
            try
            {
                Cmd = command.ExecuteNonQuery();
            }
            catch(Exception ex)
            {
                FileSupport.Instance.Write(ex.ToString());
            }
            return Cmd;
        }


        #endregion

        public DataSet ReturnDataSet(string sql, string DataSetName)
        {
            DataSet dataSet = new DataSet();
            OracleDataAdapter OraDA = new OracleDataAdapter(sql, QracleConnecting);
            OraDA.Fill(dataSet, DataSetName);
            return dataSet;
        }

        public override void Dispose()
        {
            if(mQracleConnecting.State == ConnectionState.Open)
                mQracleConnecting.Close();
        }
    }

3.sql server 派生

  public  class SQLDBSupport : DBBase
    {
        string conn;
        public SQLDBSupport(string connect)
        {
            if (mConnecting == null)
            {
                conn = connect;
                mConnecting = new SqlConnection(connect);
                mConnecting.Open();
            }
        }

        #region DB
        SqlConnection mConnecting = null;
        public SqlConnection Connecting
        {
            get
            {
                return mConnecting;
            }
        }

        public override DataTable DBGetDataTable(string sql)
        {
            try
            {
                SqlDataAdapter myda = new SqlDataAdapter(sql, Connecting); // 实例化适配器
                DataTable dt = new DataTable(); // 实例化数据表
                myda.Fill(dt); // 保存数据 
                return dt;
            }
            catch (Exception ex)
            {
                FileSupport.Instance.Write(ex.ToString());
                return null;
            }

        }

        // 执行SQL语句,返回所影响的行数   
        public override int ExecuteSQL(string sql)
        {
            int Cmd = 0;
            var Command= Connecting.CreateCommand();
            try
            {
                Cmd = Command.ExecuteNonQuery();
            }
            catch (Exception ex)
            {
                FileSupport.Instance.Write(ex.ToString());
            }
            return Cmd;
        }
        
        #endregion
public override void Dispose()
        {
            if (Connecting.State == ConnectionState.Open)
                Connecting.Close();
        }
    }