C#操作Access数据库的方法
//取得连接
public OleDbConnection getConn()
{
ConnectDatabase connstr=new ConnectDatabase();
string connStr=connstr.GetConnectionString();
OleDbConnection oledb=new OleDbConnection(connStr);
return oledb;
}
（1）采用OleDbCommand,OleDbDataReader访问数据库
1.查询
public User getUserFromName(string Searchname)
{
User tempUser=new User();
try
{
OleDbConnection oleconn=getConn();//数据库连接
string strSel="select * from MyUser where UserName='"+
Searchname+"'";//查询语句
OleDbCommand myCommand=new OleDbCommand(strSel,oleconn);//查询命令
oleconn.Open();//打开数据库连接
OleDbDataReader reader;
reader=myCommand.ExecuteReader();//执行查询命令，返回记录集
if(reader.Read())
{
tempUser.ID=(int)reader["UserID"];
tempUser.Name=reader["UserName"].ToString();
tempUser.Salary=(float)reader["UserSalary"];
tempUser.Password=reader["UserPassword"].ToString();
tempUser.Memo=reader["UserMemo"].ToString();
tempUser.Birthday=(DateTime)reader["UserBirthday"];
tempUser.Address=reader["UserAddress"].ToString();
}
else
{
throw new Exception("没有记录");
}
reader.Close();//关闭记录集
oleconn.Close();//关闭连接
}
catch(Exception e)
{
throw new Exception("打开数据库出错"+e.Message);
}
return tempUser;
}
2.插入记录
public void InsertUser(User insertuser)
{
try
{
OleDbConnection oleconn=getConn();//数据库连接
oleconn.Open();//打开数据库连接
string strSel="insert into [MyUser]([UserName],[UserPassword],
[UserSalary],[UserAddress],[UserBirthday],[UserMemo])"; //插入语句
strSel+=" values
('"+insertuser.Name+"','"+insertuser.Password+"',"+insertuser.Salary.ToSt
ring();
strSel+=",'"+insertuser.Address+"',#"+insertuser.Birthday.ToString()
+"#,'"+insertuser.Memo+"')";
OleDbCommand myCommand=new OleDbCommand(strSel,oleconn);//查询命令
myCommand.ExecuteNonQuery();
oleconn.Close();//关闭连接
}
catch(Exception e)
{
throw new Exception("打开数据库出错"+e.Message);
}
}
3.删除记录
public void DeleteUser(int m_id)
{
try
{
OleDbConnection oleconn=getConn();
oleconn.Open();
string strSel="Delete From [Myuser] where UserID="+m_id.ToString();
OleDbCommand myCommand=new OleDbCommand(strSel,oleconn);
myCommand.ExecuteNonQuery();
oleconn.Close();
}
catch(Exception e)
{
throw new Exception("删除记录出错"+e.Message);
}
}
（2）采用OleDbDataAdapter,OleDbCommandBuilder,DataSet,DataTable,DataRow访
问数据库
添加记录如下
public void InsertUserA(User insertUser)
{
using(OleDbConnection conn=getConn())
{
OleDbDataAdapter adapter = new OleDbDataAdapter();
string queryString="Select * from MyUser order by UserID";
adapter.SelectCommand = new OleDbCommand(queryString, conn);
OleDbCommandBuilder builder = new OleDbCommandBuilder(adapter);
// builder.QuotePrefix="[";
// builder.QuoteSuffix="]";
conn.Open();
DataSet users = new DataSet();
adapter.Fill(users,"MyUser");
DataTable dt=new DataTable();
dt=users.Tables["MyUser"];
DataRow r=dt.NewRow();
r["UserName"]=insertUser.Name;
r["UserPassword"]=insertUser.Password;
r["UserAddress"]=insertUser.Address;
r["UserSalary"]=insertUser.Salary;
r["UserBirthday"]=insertUser.Birthday;
r["UserMemo"]=insertUser.Memo;
dt.Rows.Add(r);
adapter.Update(users, "MyUser");
}
}
需要注意字段不能和关键字相同，否则会出现Insert into出错的提示。解决办法在
前一篇
(3)采用参数化查询的方式
public class AccessUtil
{
public AccessUtil()
{
}
private string connString;
public string ConnString
{
get { return connString; }
set { connString = value; }
}
public AccessUtil(string connstr)
{
this.connString = connstr;
}
//带参数的插入语句,返回值为id关键字的值,单条插入语句
public int ExecuteInsert(string SQL, OleDbParameter[]
parameters)
{
using(OleDbConnection conn=new OleDbConnection(connString))
{
OleDbCommand cmd = new OleDbCommand(SQL, conn);
try
{
conn.Open();
if (parameters!=null)
{
cmd.Parameters.AddRange(parameters);
}
cmd.ExecuteNonQuery();
cmd.CommandText = @"Select @@identity";
int value = Int32.Parse(cmd.ExecuteScalar().ToString
());
return value;
}
catch (System.Exception e)
{
throw e;
}
}
}
//不带参数的插入语句，返回值为关键字的值
public int ExecuteInsert(string SQL)
{
return ExecuteInsert(SQL, null);
}
//带参数的插入、删除、更新语句，返回受影响的记录的个数
public int ExecuteNoQuery(string SQL, OleDbParameter[]
parameters)
{
using(OleDbConnection conn=new OleDbConnection(connString))
{
conn.Open();
OleDbCommand cmd = new OleDbCommand(SQL, conn);
try
{
if (parameters!=null)
{
cmd.Parameters.AddRange(parameters);
}
int rows=cmd.ExecuteNonQuery();
return rows;
}
catch (System.Exception e)
{
throw e;
}
}
}
//不带参数的插入、删除、更新语句，返回受影响的记录的个数
public int ExecuteNoQuery(string SQL)
{
return ExecuteNoQuery(SQL, null);
}
//带参数的查询语句，返回所查询到的记录集
public DataSet ExecuteQuery(string SQL, OleDbParameter[]
parameters)
{
using(OleDbConnection conn=new OleDbConnection(connString))
{
DataSet ds = new DataSet();
try
{
conn.Open();
OleDbDataAdapter da = new OleDbDataAdapter(SQL,
conn);
if (parameters != null)
{
da.SelectCommand.Parameters.AddRange(parameters);
}
da.Fill(ds, "ds");
}
catch(System.Exception e)
{
throw e;
}
return ds;
}
}
//不带参数的查询，返回所查询到的记录集
public DataSet ExecuteQuery(string SQL)
{
return ExecuteQuery(SQL, null);
}
}
class ManageUser
{
//Access数据库工具对象
AccessUtil accessutil = new AccessUtil
(ConnectDatabase.GetConnectionString());
public ArrayList GetAllUserArr()//获得User表中的所有记录，存储进
ArrayList。
{
string SQL = "select * from MyUser order by ID";
DataSet ds=accessutil.ExecuteQuery(SQL);//返回的临时表的名称
为“ds”
/*
ArrayList arr = new ArrayList();
for (int i = 0; i < ds.Tables
["ds"].Rows.Count;i++ )
{
arr.Add(DataRow2User(ds.Tables["ds"].Rows
[i]));
}*/
ArrayList arr = DataTable2ArrayList(ds.Tables["ds"]);
return arr;
}
public DataSet GetAllUserDataSet()//存储成DataSet
{
string SQL = "select * from MyUser order by ID";
DataSet ds = accessutil.ExecuteQuery(SQL);
return ds;
}
private User DataRow2User(DataRow dr)//将数据表中的一条记录转换为
一个User类的实例
{
User user = new User();
user.ID = Int32.Parse(dr["ID"].ToString());
user.Name = dr["Name"].ToString();
user.Address = dr["Address"].ToString();
user.Birthday = Convert.ToDateTime(dr
["Birthday"].ToString());
user.Memo = dr["Memo"].ToString();
user.Salary =(float) Convert.ToDouble(dr
["Salary"].ToString());
user.Password = dr["Password"].ToString();
return user;
}
private ArrayList DataTable2ArrayList(DataTable dt)//将一个表中的
记录转化为ArrayList对象
{
ArrayList tempArr = new ArrayList();
DataTableReader dr = new DataTableReader(dt);
while(dr.Read())
{
User user = new User();
user.ID = Int32.Parse(dr["ID"].ToString());
user.Name = dr["Name"].ToString();
user.Address = dr["Address"].ToString();
user.Birthday = Convert.ToDateTime(dr["Birthday"].ToString());
user.Memo = dr["Memo"].ToString();
user.Salary = (float)Convert.ToDouble(dr["Salary"].ToString
());
user.Password = dr["Password"].ToString();
tempArr.Add(user);
}
return tempArr;
}
public DataSet GetUserByName(string name)
{
String SQL = "Select * from MyUser where Name=?";
OleDbParameter[] parameter = new OleDbParameter[1];
parameter[0] = new OleDbParameter("@Name",
OleDbType.VarChar);
parameter[0].Value = name;
DataSet dt= accessutil.ExecuteQuery(SQL, parameter);
return dt;
}
public int InsertUser(User inUser)
{
String SQL = "insert into [MyUser]([Name],[Password],
[Salary],[Address],[Birthday],[Memo]) values(?,?,?,?,?,?)";
OleDbParameter[] parameters = new OleDbParameter[6];
parameters[0] = new OleDbParameter("@Name",
OleDbType.VarChar);
parameters[0].Value = inUser.Name;
parameters[1] = new OleDbParameter("@Password",
OleDbType.VarChar);
parameters[1].Value = inUser.Password;
parameters[2] = new OleDbParameter("@Salary",
OleDbType.Single);
parameters[2].Value = inUser.Salary;
parameters[3] = new OleDbParameter("@Address",
OleDbType.VarChar);
parameters[3].Value = inUser.Address;
parameters[4] = new OleDbParameter("@Birthday",
OleDbType.Date);
parameters[4].Value = inUser.Birthday;
parameters[5] = new OleDbParameter("@Memo",
OleDbType.VarChar);
parameters[5].Value = inUser.Memo;
return accessutil.ExecuteInsert(SQL, parameters);
}
public void DelUserById(int id)
{
String SQL = "DELETE FROM [MyUser] where ID=?";
OleDbParameter[] parameters = new OleDbParameter[1];
parameters[0] = new OleDbParameter("@ID", OleDbType.Integer);
parameters[0].Value = id;
accessutil.ExecuteNoQuery(SQL, parameters);
}
public void UpdateUser(User userupdate)
{
String SQL = "update [MyUser] Set [Name]=?,[Password]=?,
[Salary]=?,[Address]=?,[Birthday]=?,[Memo]=? where [ID]=?";
OleDbParameter[] parameters = new OleDbParameter[7];
parameters[0] = new OleDbParameter("@Name",
OleDbType.VarChar);
parameters[0].Value = userupdate.Name;
parameters[1] = new OleDbParameter("@Password",
OleDbType.VarChar);
parameters[1].Value = userupdate.Password;
parameters[2] = new OleDbParameter("@Salary",
OleDbType.Single);
parameters[2].Value = userupdate.Salary;
parameters[3] = new OleDbParameter("@Address",
OleDbType.VarChar);
parameters[3].Value = userupdate.Address;
parameters[4] = new OleDbParameter("@Birthday",
OleDbType.Date);
parameters[4].Value = userupdate.Birthday;
parameters[5] = new OleDbParameter("@Memo",
OleDbType.VarChar);
parameters[5].Value = userupdate.Memo;
parameters[6] = new OleDbParameter("@ID", OleDbType.Integer);
parameters[6].Value = userupdate.ID;
accessutil.ExecuteNoQuery(SQL, parameters);
}
}
