c#下各种数据库操作的封装！(支持ACCESS,SQLSERVER,DB2,ORACLE,MYSQL)（三）

各派生类的具体实现，此时只要实现DBAccess的各个虚函数即可。


        private class Access : DBAccess




        ...{


            public Access(DBType type)


                : base(type)




            ...{


            }




            protected override void InitConn(string strServer, string strDataBase, string strUser, string strPwd)




            ...{


                string strConn = "Provider = ";


                switch (strDataBase.Substring(strDataBase.LastIndexOf('.') + 1).ToLower())




                ...{


                    case "mdb":     // 2000, 2003


                        strConn += "Microsoft.Jet.OleDb.4.0;";


                        break;




                    case "accdb":   // 2007


                        strConn += "Microsoft.ACE.OLEDB.12.0;";


                        break;




                    default:


                        throw (new Exception("Unknown Access Version."));


                    //break;


                }


                strConn += CON_strDataBase + " = " + strDataBase;


                //strConn += CON_strUser + " = " + strUser;


                //strConn += CON_strPwd + " = " + strPwd;


                base.m_oConn = new OleDbConnection(strConn);


            }




            protected override DbCommand GetCmd(string strCmd)




            ...{


                return new OleDbCommand(strCmd, (OleDbConnection)base.m_oConn);


            }




            protected override DbDataAdapter DbAdp




            ...{




                get ...{ return new OleDbDataAdapter(); }


            }




            public override DataTable Tables




            ...{


                get




                ...{




                    return ((OleDbConnection)base.m_oConn).GetOleDbSchemaTable(OleDbSchemaGuid.Tables, new object[] ...{ null, null, null, "Table" });


                }


            }




            public override DataTable GetColumns()




            ...{


                DataTable dt = new DataTable();


                foreach (DataRow row in this.Tables.Rows)




                ...{


                    dt.Merge(this.GetColumns(row["TABLE_NAME"].ToString()));


                }


                return dt;


            }




            public override DataTable GetColumns(string strTable)




            ...{




                return ((OleDbConnection)base.m_oConn).GetOleDbSchemaTable(OleDbSchemaGuid.Columns, new object[] ...{ null, null, strTable, null });


            }


        }




        private class SQL : DBAccess




        ...{


            public SQL(DBType type)


                : base(type)




            ...{


            }




            protected override void InitConn(string strServer, string strDataBase, string strUser, string strPwd)




            ...{


                string strConn = CON_strServer + " = " + strServer + ";";


                strConn += CON_strDataBase + " = " + strDataBase + ";";


                strConn += CON_strUser + " = " + strUser + ";";


                strConn += CON_strPwd + " = " + strPwd + ";";


                strConn += CON_strConnTimeOut;


                base.m_oConn = new SqlConnection(strConn);


            }




            protected override DbCommand GetCmd(string strCmd)




            ...{


                return new SqlCommand(strCmd, (SqlConnection)base.m_oConn);


            }




            protected override DbDataAdapter DbAdp




            ...{




                get ...{ return new SqlDataAdapter(); }


            }




            public override DataTable Tables




            ...{




                get ...{ return ((SqlConnection)base.m_oConn).GetSchema("Tables", null); }


            }




            public override DataTable GetColumns()




            ...{


                return ((SqlConnection)base.m_oConn).GetSchema("Columns", null);


            }




            public override DataTable GetColumns(string strTable)




            ...{




                return ((SqlConnection)base.m_oConn).GetSchema("Columns", new string[] ...{ null, null, strTable, null });


            }


        }