C# 操作数据库就的那点代码
操作数据库的那点代码,别在费劲每个数据库都写一遍SQLHelper,SQLiteHelper,OleDbHelper,了,这里都有了.
接口不发了,自己抽取定义就行了.
public abstract class DbHelperBase : IDbHelper
{
/// <summary>
/// 直接获得连接字符串
/// </summary>
/// <param name="connStr"></param>
public DbHelperBase(string connStr)
{
_ConnStr = connStr;
_LockExecNonQuery = new object();
_LockGetDataReader = new object();
_LockGetScalar = new object();
_LockGetDataSet = new object();
}
/// <summary>
/// 连接字符串
/// </summary>
protected string _ConnStr;
/// <summary>
/// 是否事务
/// </summary>
bool _IsTrans = false;
object _LockExecNonQuery;
object _LockGetDataReader;
object _LockGetScalar;
object _LockGetDataSet;
protected abstract DbConnection DBConnectionObj { get; }
protected abstract DbCommand DbCommandObj { get; }
protected abstract DbDataAdapter DbDataAdapterObj { get; }
protected DbTransaction DbTransObj;
/// <summary>
/// 当前连接
/// </summary>
public DbConnection CurrentConnection
{
get
{
return DBConnectionObj;
}
}
/// <summary>
/// 执行sql问错误写日志方法
/// </summary>
protected virtual void WriteErrLog(Exception ex, string sqlText, params DbParameter[] param)
{
StringPlus logs = new StringPlus();
logs.AppendLine("SQL文本:");
logs.AppendLine(sqlText);
logs.AppendLine("Sql文参数:");
if (param != null)
{
foreach (DbParameter item in param)
{
logs.AppendSpaceLine(1, "参数名:{0},参数值:{1}", item.ParameterName, item.Value);
}
}
logs.AppendLine("原始错误:");
logs.AppendLine(ex.Message);
LogHelper.WriteLog("DbErrorLog", logs.ToString());
}
/// <summary>
/// 打开连接,如果已经打开则什么都不执行了
/// </summary>
protected virtual void OpenConnection()
{
if (DBConnectionObj.State != ConnectionState.Open)
{
DBConnectionObj.ConnectionString = _ConnStr;
DBConnectionObj.Open();
}
}
/// <summary>
/// 关闭连接,如果没有开始事务或连接打开时才关闭
/// </summary>
void CloseConnect()
{
if (!_IsTrans)
{
if (DBConnectionObj.State == ConnectionState.Open)
{
DBConnectionObj.Close();
DBConnectionObj.Dispose();
}
}
}
/// <summary>
/// 给当前DbCommand对象赋值,并且OpenConnection();
/// </summary>
void SetCommandAndOpenConnect(string sqlText, CommandType cmdType, params DbParameter[] param)
{
//按说赋值Connection,CommandType,是不用多次赋值的
DbCommandObj.CommandType = cmdType;
DbCommandObj.Connection = DBConnectionObj;
DbCommandObj.Parameters.Clear();
if (param != null)
{
DbCommandObj.Parameters.AddRange(param);
}
DbCommandObj.CommandText = sqlText;
OpenConnection();
}
/// <summary>
/// 开始执行事务
/// </summary>
public virtual void TransStart()
{
OpenConnection();
DbTransObj = DBConnectionObj.BeginTransaction();
DbCommandObj.Transaction = DbTransObj;
_IsTrans = true;
}
/// <summary>
/// 事务提交
/// </summary>
public virtual void TransCommit()
{
_IsTrans = false;
DbTransObj.Commit();
CloseConnect();
}
/// <summary>
/// 事务回滚
/// </summary>
public virtual void TransRollback()
{
_IsTrans = false;
DbTransObj.Rollback();
CloseConnect();
}
/// <summary>
/// 执行一条指定命令类型(SQL语句或存储过程等)的SQL语句,返回所影响行数
/// </summary>
public virtual int ExecNonQuery(string sqlText, CommandType cmdType, params DbParameter[] param)
{
lock (_LockExecNonQuery)
{
try
{
SetCommandAndOpenConnect(sqlText, cmdType, param);
return DbCommandObj.ExecuteNonQuery();
}
catch (Exception ex)
{
WriteErrLog(ex, sqlText, param);
throw new DbDataException();
}
finally
{
CloseConnect();
}
}
}
/// <summary>
/// 执行一条普通SQL语句的命令,返回所影响行数
/// </summary>
public virtual int ExecNonQuery(string sqlText, params DbParameter[] param)
{
return ExecNonQuery(sqlText, CommandType.Text, param);
}
/// <summary>
/// 获得DataReader对象
/// </summary>
public virtual DbDataReader GetDataReader(string sqlText, CommandType cmdType, CommandBehavior cmdBehavior, params DbParameter[] param)
{
lock (_LockGetDataReader)
{
try
{
SetCommandAndOpenConnect(sqlText, cmdType, param);
DbDataReader dbReader = DbCommandObj.ExecuteReader(cmdBehavior);
return dbReader;
}
catch (Exception ex)
{
WriteErrLog(ex, sqlText, param);
throw new DbDataException();
}
finally
{
//DataReader用dbReader对象来关闭,即使非事务也是,不要把注释取消
//CloseConnect();
}
}
}
/// <summary>
/// 获得DataReader对象
/// </summary>
public virtual DbDataReader GetDataReader(string sqlText, CommandType cmdType, params DbParameter[] param)
{
CommandBehavior cmdBehavior;
if (_IsTrans)
{
cmdBehavior = CommandBehavior.Default;
}
else
{
//非事务时,关闭DataReader则关闭当前连接
cmdBehavior = CommandBehavior.CloseConnection;
}
return GetDataReader(sqlText, cmdType, cmdBehavior, param);
}
/// <summary>
/// 执行sql语句返回DataReader对象
/// </summary>
public virtual DbDataReader GetDataReader(string sqlText, params DbParameter[] param)
{
return GetDataReader(sqlText, CommandType.Text, param);
}
/// <summary>
/// 获得首行首列
/// </summary>
public virtual object GetScalar(string sqlText, CommandType cmdType, params DbParameter[] param)
{
lock (_LockGetScalar)
{
try
{
SetCommandAndOpenConnect(sqlText, cmdType, param);
return DbCommandObj.ExecuteScalar();
}
catch (Exception ex)
{
WriteErrLog(ex, sqlText, param);
throw new DbDataException();
}
finally
{
CloseConnect();
}
}
}
/// <summary>
/// 执行SQL语句,返回首行首列
/// </summary>
public virtual object GetScalar(string sqlText, params DbParameter[] param)
{
return GetScalar(sqlText, CommandType.Text, param);
}
/// <summary>
/// 执行一条SQL语句返回DataSet对象
/// </summary>
public virtual DataSet GetDataSet(string sqlText, CommandType cmdType, params DbParameter[] param)
{
lock (_LockGetDataSet)
{
try
{
SetCommandAndOpenConnect(sqlText, cmdType, param);
DbDataAdapterObj.SelectCommand = DbCommandObj;
DataSet ds = new DataSet();
DbDataAdapterObj.Fill(ds);
return ds;
}
catch (Exception ex)
{
WriteErrLog(ex, sqlText, param);
throw new DbDataException();
}
finally
{
CloseConnect();
}
}
}
/// <summary>
/// 执行一条SQL语句返回DataSet对象
/// </summary>
public virtual DataSet GetDataSet(string sqlText, params DbParameter[] param)
{
return GetDataSet(sqlText, CommandType.Text, param);
}
/// <summary>
/// 执行一条SQL语句返回DataTable对象(调用GetDataSet)
/// </summary>
public virtual DataTable GetDataTable(string sqlText, params DbParameter[] param)
{
return GetDataTable(sqlText, CommandType.Text, param);
}
/// <summary>
/// 执行一条SQL语句返回DataTable对象(调用GetDataSet)
/// </summary>
public virtual DataTable GetDataTable(string sqlText, CommandType cmdType, params DbParameter[] param)
{
return (GetDataSet(sqlText, cmdType, param)).Tables[0];
}
}
下面是一个sqlserver的实现
public class SQLHelper : DbHelperBase
{
public SQLHelper(string connStr)
: base(connStr)
{ }
SqlConnection _DBConnectionObj;
SqlCommand _DbCommandObj;
SqlDataAdapter _DbDataAdapterObj;
protected override DbConnection DBConnectionObj
{
get
{
//SqlBulkCopy aa = new SqlBulkCopy(new SqlConnection());
if (_DBConnectionObj == null)
{
_DBConnectionObj = new SqlConnection(_ConnStr);
}
return _DBConnectionObj;
}
}
protected override DbCommand DbCommandObj
{
get
{
if (_DbCommandObj == null)
{
_DbCommandObj = new SqlCommand();
}
return _DbCommandObj;
}
}
protected override DbDataAdapter DbDataAdapterObj
{
get
{
if (_DbDataAdapterObj == null)
{
_DbDataAdapterObj = new SqlDataAdapter();
}
return _DbDataAdapterObj;
}
}
}
使用示例:
IDbHelper sql = new SQLHelper("连接字符串");
try
{
sql.TransStart(); //事务开始
sql.ExecNonQuery("执行sql语句1"); //执行(增删改查)一条sql语句
sql.ExecNonQuery("执行sql语句2"); //执行(增删改查)一条sql语句
DataTable dt = sql.GetDataTable("查询sql语句1"); //获取一些数据
sql.TransCommit(); //提交事务
}
catch (Exception ex)
{
sql.TransRollback(); //事务回滚
throw;
}