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。