c#下各种数据库操作的封装！(支持ACCESS,SQLSERVER,DB2,ORACLE,MYSQL)（二）

作者：PeterXu  来源：Blog.CSDN  Blog: http://blog.csdn.net/peterreg/

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使用静态工厂模式，通过传入枚举型参数 ，动态创建访问实例

实现模式上采用基本实现接口，派生类继承基类的虚函数，从而实现代码的耦合较低，有很好的扩展性。

public   enum  DBType

     ... {

        Access,

        SQL,

        DB2,

        Oracle,

        MySQL

    }

  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;}

        }

   }