看李建忠的讲座之后把以前写数据库操作也改了改.

李建忠老师在讲座中,谁容易变化就把谁拿出来

由于以前我写了好几类分别对应的不用数据库

现在把它们都抽象出来,但是不知道这样是不是对

现在把代码贴出来大家一个讨论一下

听了李建的设计模式之后,也按李老师的相法去写,但是不知道自己写得哪一种模式

由于我的个人原因吧,接触到项目少,所以在听完之后也没有去做相应的练习吧

望各位多我指点吧

下面是代码是我把几个以前写的类有Oledb,sql,Oracle等几个操作数据常的几种方法抽象出来了.

using  System; using  System.Collections.Generic; using  System.Text; using  System.Data; namespace  LiaoHaiBing.Data ... {    public abstract class DatabaseFactoy    ...{        //数据连接        public abstract IDbConnection Connection...{get;}        //建立Command对象        public abstract IDbCommand Command();        //建立Command对象        public abstract IDbCommand Command(string executeString);        //返回受影响得行数        public abstract int ExecuteNonQuery(string executeString);        //返回首行首列的值        public abstract object ExecuteScalar(string executeString);        //返回只读数据        public abstract IDataReader ExecuteReader(string executeString);        //返回一个DataTable        public abstract DataTable GetDataTable(string executeString);        //返回一个DataSet        public abstract DataSet GetDataSet(string executeString);    }} SqlDatabase 数据操作类,是对sql数据进行常操作的几个方法 using  System; using  System.Collections.Generic; using  System.Text; using  System.Data; using  System.Data.SqlClient; namespace  LiaoHaiBing.Data ... {    public class SqlDatabase : DatabaseFactoy     ...{        //连接数据库字符串        string _connectionString = ConnectionString.connectionString.DataBaseConnectionString;        private static SqlDatabase _sqlDatabase;        public static SqlDatabase sqlDatabase        ...{            get ...{                if (_sqlDatabase == null)                ...{                    _sqlDatabase = new SqlDatabase();                }                return _sqlDatabase;            }        }        public override IDbConnection Connection        ...{            get            ...{                SqlConnection cn = new SqlConnection(_connectionString);                try                ...{                    cn.Open();                    return cn;                }                catch                ...{                    throw new Exception("创建数据连接时出现在错误");                }            }        }        public override IDbCommand Command()        ...{            SqlConnection cn = (SqlConnection)this.Connection;            SqlCommand cmd = new SqlCommand();            try            ...{                if (cn == null)                ...{                    throw new Exception("创建数据连接时出现在问题.");                }                else                ...{                    cmd.Connection = cn;                    return cmd;                }            }            catch            ...{                throw new Exception("创建命令对象时出现在问题.");            }        }        public override IDbCommand Command(string executeString)        ...{            SqlConnection cn = (SqlConnection)Connection;            SqlCommand cmd = new SqlCommand();            try            ...{                if (cn == null)                ...{                    throw new Exception("创建数据连接时出现在问题.");                }                else                ...{                    cmd.Connection = cn;                    cmd.CommandText = executeString;                    return cmd;                }            }            catch            ...{                throw new Exception("创建命令对象时出现在问题.");            }        }        public override int ExecuteNonQuery(string executeString)        ...{            SqlCommand cmd = (SqlCommand)Command(executeString);            try            ...{                return cmd.ExecuteNonQuery();            }            catch (SqlException se)            ...{                throw new Exception("在执行操作时出现在问题," + se.Message);            }            finally            ...{                cmd.Connection.Dispose();                cmd.Connection.Close();                cmd.Dispose();            }        }        public override DataTable GetDataTable(string executeString)        ...{            SqlConnection cn = (SqlConnection)Connection;            SqlDataAdapter sda;            try            ...{                sda = new SqlDataAdapter(executeString, cn);                DataTable dt = new DataTable();                sda.Fill(dt);                return dt;            }            catch            ...{                throw new Exception("填充数据时发生错误。");            }            finally            ...{                cn.Dispose();                cn.Close();            }        }        public override DataSet GetDataSet(string executeString)        ...{            SqlConnection cn = (SqlConnection)Connection;            SqlDataAdapter sda;            try            ...{                sda = new SqlDataAdapter(executeString, cn);                DataSet ds = new DataSet();                sda.Fill(ds);                return ds;            }            catch            ...{                throw new Exception("填充数据集时出现错误。");            }            finally            ...{                cn.Dispose();                cn.Close();            }        }        public override object ExecuteScalar(string executeString)        ...{            SqlCommand cmd = (SqlCommand)Command(executeString);            try            ...{                return cmd.ExecuteScalar();            }            catch (SqlException se)            ...{                throw new Exception("你的sql语句有问题," + se.Message);            }            finally            ...{                cmd.Connection.Dispose();                cmd.Connection.Close();                cmd.Dispose();            }        }        public override IDataReader ExecuteReader(string executeString)        ...{            SqlCommand cmd = (SqlCommand)Command(executeString);            try            ...{                return cmd.ExecuteReader(CommandBehavior.CloseConnection);            }            catch (SqlException se)            ...{                throw new Exception("在读取数据的时问题了, " + se.Message);            }            finally            ...{                cmd.Dispose();            }        }    }}

 OleDbDatabase 数据操作类,是对Access数据进行常规操作的几个方法

using  System; using  System.Collections.Generic; using  System.Text; using  System.Data; using  System.Data.OleDb; namespace  LiaoHaiBing.Data.OleDb ... {    public class OleDbDatabase : DatabaseFactoy    ...{        string _connectionString = ConnectionString.connectionString.DataBaseConnectionString;        private static OleDbDatabase _oleDbDatabase;        public static OleDbDatabase oleDbDatabase        ...{            get            ...{                if (_oleDbDatabase == null)                ...{                    _oleDbDatabase = new OleDbDatabase();                }                return _oleDbDatabase;            }        }        public override IDbConnection Connection        ...{            get ...{                OleDbConnection cn = new OleDbConnection(_connectionString);                try                ...{                    cn.Open();                    return cn;                }                catch(OleDbException ee)                ...{                    throw new Exception("创建数据连接时出现在错误" + ee.Message);                }            }        }        public override IDbCommand Command()        ...{            IDbConnection cn = this.Connection;            IDbCommand cmd = new OleDbCommand();            try            ...{                if (cn == null)                ...{                    throw new Exception("创建数据连接时出现在问题.");                }                else                ...{                    cmd.Connection = cn;                    return cmd;                }            }            catch            ...{                throw new Exception("创建命令对象时出现在问题.");            }        }        public override IDbCommand Command(string executeString)        ...{            IDbConnection cn = this.Connection;            IDbCommand cmd = new OleDbCommand();            try            ...{                if (cn == null)                ...{                    throw new Exception("创建数据连接时出现在问题.");                }                else                ...{                    cmd.Connection = cn;                    cmd.CommandText = executeString;                    return cmd;                }            }            catch            ...{                throw new Exception("创建命令对象时出现在问题.");            }        }        public override int ExecuteNonQuery(string executeString)        ...{            IDbCommand cmd = this.Command(executeString);            try            ...{                return cmd.ExecuteNonQuery();            }            catch (OleDbException se)            ...{                throw new Exception("在执行操作时出现在问题," + se.Message);            }            finally            ...{                cmd.Connection.Dispose();                cmd.Connection.Close();                cmd.Dispose();            }        }        public override IDataReader ExecuteReader(string executeString)        ...{            IDbCommand cmd = this.Command(executeString);            try            ...{                return cmd.ExecuteReader(CommandBehavior.CloseConnection);            }            catch (OleDbException se)            ...{                throw new Exception("在读取数据的时问题了, " + se.Message);            }            finally            ...{                //cmd.Dispose();            }        }        public override object ExecuteScalar(string executeString)        ...{            IDbCommand cmd = this.Command(executeString);            try            ...{                return cmd.ExecuteScalar();            }            catch (OleDbException se)            ...{                throw new Exception("你的sql语句有问题," + se.Message);            }            finally            ...{                cmd.Connection.Dispose();                cmd.Connection.Close();                cmd.Dispose();            }        }        public override DataTable GetDataTable(string executeString)        ...{            OleDbConnection cn = (OleDbConnection)Connection;            OleDbDataAdapter sda;            try            ...{                sda = new OleDbDataAdapter(executeString,cn);                DataTable dt = new DataTable();                sda.Fill(dt);                return dt;            }            catch            ...{                throw new Exception("填充数据时发生错误。");            }            finally            ...{                cn.Dispose();                cn.Close();            }        }        public override DataSet GetDataSet(string executeString)        ...{            OleDbConnection cn = (OleDbConnection)Connection;            OleDbDataAdapter sda;            try            ...{                sda = new OleDbDataAdapter(executeString, cn);                DataSet ds = new DataSet();                sda.Fill(ds);                return ds;            }            catch            ...{                throw new Exception("填充数据集时出现错误。");            }            finally            ...{                cn.Dispose();                cn.Close();            }        }    }}

如果你要数据以前是Access的,用得时候只要LiaoHaiBing.Data.DatabaseFactoy db = new OleDbDatabase() 就行了,不用 OleDbDatabase db = new OleDbDatabase() 这样了,如果这样的话,那不用那个抽象也可以了现在就是如果当你的数据由Access变成Sql了的话,只需将LiaoHaiBing.Data.DatabaseFactoy db = new OleDbDatabase() 改一成 LiaoHaiBing.Data.DatabaseFactoy db = new SqlDatabase() 就行了其它的什么也都不用改这样用起来是不是好放便多了呢。当然这两个数据库当中表的结构要一样，要不能的话会出问题。