c#下各种数据库操作的封装！(支持ACCESS,SQLSERVER,DB2,ORACLE,MYSQL)（四）

整个例子的完整代码如下，VS2008下编译测试通过，本人已通过它实现N个项目，欢迎大家评测，谢谢指教

public   enum  DBType

     ... {

        Access,

        SQL,

        DB2,

        Oracle,

        MySQL

    }

     public   interface  IDBAccess

     ... {

        void Init(string strServer, string strDataBase, string strUser, string strPwd);

        void Open();

        void Close();

        bool TestConn();

        int RunNoQuery(string strCmd);

        DataTable RunQuery(string strCmd);

        DBType DBType ...{ get;}

        int GetFiledMax(string strTable, string strField);

        DataTable Tables ...{ get; }

        DataTable GetColumns();

        DataTable GetColumns(string strTable);

    }

     public   static   class  DBAccessFactory

     ... {

        public static IDBAccess Create(DBType type)

        ...{

            IDBAccess IRet = null;

            switch (type)

            ...{

                case DBType.Access:

                    IRet = new Access(type);

                    break;

                case DBType.SQL:

                    IRet = new SQL(type);

                    break;

                default:

                    break;

            }

            return IRet;

        }

        private abstract class DBAccess : IDBAccess

        ...{

            protected DbConnection m_oConn = null;

            protected const string CON_strServer = "Server";

            protected const string CON_strDataBase = "Data Source";

            protected const string CON_strUser = "UID";

            protected const string CON_strPwd = "PWD";

            protected const string CON_strConnTimeOut = "Connect Timeout = 2";

            private DBType m_eDBType = DBType.Access;

            protected DBAccess(DBType type)

            ...{

                this.m_eDBType = type;

            }

            public DBType DBType

            ...{

                get ...{ return this.m_eDBType; }

            }

            public void Init(string strServer, string strDataBase, string strUser, string strPwd)

            ...{

                this.InitConn(strServer, strDataBase, strUser, strPwd);

            }

            public void Open()

            ...{

                if (this.m_oConn != null)

                ...{

                    this.m_oConn.Open();

                }

            }

            public int RunNoQuery(string strCmd)

            ...{

                int iRet = 0;

                try

                ...{

                    DbCommand oCmd = this.GetCmd(strCmd);

                    if (oCmd != null)

                    ...{

                        iRet = oCmd.ExecuteNonQuery();

                    }

                }

                catch (Exception ex)

                ...{

                    throw (new Exception(ex.Message));

                }

                return iRet;

            }

            public int GetFiledMax(string strTable, string strField)

            ...{

                int iRet = -1;

                DataTable dt = this.RunQuery("Select Max(" + strField + ") From " + strTable);

                if (dt != null && dt.Rows.Count == 1)

                ...{

                    iRet = dt.Rows[0][0] is DBNull ? 0 : Convert.ToInt32(dt.Rows[0][0]);

                }

                return iRet;

            }

            public DataTable RunQuery(string strCmd)

            ...{

                DataTable dt = new DataTable();

                DbDataAdapter adp = this.DbAdp;

                adp.SelectCommand = this.GetCmd(strCmd);

                adp.Fill(dt);

                return dt;

            }

            public void Close()

            ...{

                if (this.m_oConn != null && this.m_oConn.State == System.Data.ConnectionState.Open)

                ...{

                    this.m_oConn.Close();

                }

            }

            public bool TestConn()

            ...{

                bool bRet = true;

                try

                ...{

                    if (this.m_oConn.State != System.Data.ConnectionState.Open)

                    ...{

                        this.m_oConn.Open();

                    }

                    bRet = this.m_oConn.State == System.Data.ConnectionState.Open;

                }

                catch

                ...{

                    bRet = false;

                }

                this.Close();

                return bRet;

            }

            public abstract DataTable Tables ...{ get; }

            public abstract DataTable GetColumns();

            public abstract DataTable GetColumns(string strTable);

            protected abstract void InitConn(string strServer, string strDataBase, string strUser, string strPwd);

            protected abstract DbCommand GetCmd(string strCmd);

            protected abstract DbDataAdapter DbAdp ...{ get;}

        }

        Access, SQL#region Access, SQL

        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 });

            }

        }

        #endregion

    }