C#access数据库连接代码Word格式.docx
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- 上传时间:2023-01-16
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- 页数:15
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C#access数据库连接代码Word格式.docx
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{
//数据库连接字符串(web.config来配置),可以动态更改connectionString支持多数据库.
//publicstaticstringconnectionString="
|DataDirectory|"
+"
pp.asp"
;
publicstaticstringconnectionString="
Provider=Microsoft.Jet.OLEDB.4.0;
DataSource="
+System.Web.HttpContext.Current.Server.MapPath(@"
/db/dbtest.mdb"
);
publicDbHelperOleDb()
}
#region公用方法
publicstaticintGetMaxID(stringFieldName,stringTableName)
stringstrsql="
selectmax("
+FieldName+"
)+1from"
+TableName;
objectobj=DbHelperSQL.GetSingle(strsql);
if(obj==null)
return1;
else
returnint.Parse(obj.ToString());
publicstaticboolExists(stringstrSql)
objectobj=DbHelperSQL.GetSingle(strSql);
intcmdresult;
if((Object.Equals(obj,null))||(Object.Equals(obj,System.DBNull.Value)))
cmdresult=0;
cmdresult=int.Parse(obj.ToString());
if(cmdresult==0)
returnfalse;
returntrue;
publicstaticboolExists(stringstrSql,paramsOleDbParameter[]cmdParms)
objectobj=GetSingle(strSql,cmdParms);
#endregion
#region执行简单SQL语句
///执行SQL语句,返回影响的记录数
paramname="
SQLString"
>
SQL语句<
/param>
returns>
影响的记录数<
/returns>
publicstaticintExecuteSql(stringSQLString)
using(OleDbConnectionconnection=newOleDbConnection(connectionString))
using(OleDbCommandcmd=newOleDbCommand(SQLString,connection))
try
connection.Open();
introws=cmd.ExecuteNonQuery();
returnrows;
catch(System.Data.OleDb.OleDbExceptionE)
connection.Close();
thrownewException(E.Message);
///执行多条SQL语句,实现数据库事务。
SQLStringList"
多条SQL语句<
publicstaticvoidExecuteSqlTran(ArrayListSQLStringList)
using(OleDbConnectionconn=newOleDbConnection(connectionString))
conn.Open();
OleDbCommandcmd=newOleDbCommand();
cmd.Connection=conn;
OleDbTransactiontx=conn.BeginTransaction();
cmd.Transaction=tx;
for(intn=0;
n<
SQLStringList.Count;
n++)
stringstrsql=SQLStringList[n].ToString();
if(strsql.Trim().Length>
1)
cmd.CommandText=strsql;
cmd.ExecuteNonQuery();
tx.Commit();
tx.Rollback();
///执行带一个存储过程参数的的SQL语句。
content"
参数内容,比如一个字段是格式复杂的文章,有特殊符号,可以通过这个方式添加<
publicstaticintExecuteSql(stringSQLString,stringcontent)
OleDbCommandcmd=newOleDbCommand(SQLString,connection);
System.Data.OleDb.OleDbParametermyParameter=newSystem.Data.OleDb.OleDbParameter("
@content"
OleDbType.VarChar);
myParameter.Value=content;
cmd.Parameters.Add(myParameter);
finally
cmd.Dispose();
///向数据库里插入图像格式的字段(和上面情况类似的另一种实例)
strSQL"
fs"
图像字节,数据库的字段类型为image的情况<
publicstaticintExecuteSqlInsertImg(stringstrSQL,byte[]fs)
OleDbCommandcmd=newOleDbCommand(strSQL,connection);
@fs"
OleDbType.Binary);
myParameter.Value=fs;
///执行一条计算查询结果语句,返回查询结果(object)。
计算查询结果语句<
查询结果(object)<
publicstaticobjectGetSingle(stringSQLString)
objectobj=cmd.ExecuteScalar();
returnnull;
returnobj;
catch(System.Data.OleDb.OleDbExceptione)
thrownewException(e.Message);
///执行查询语句,返回OleDbDataReader
查询语句<
OleDbDataReader<
publicstaticOleDbDataReaderExecuteReader(stringstrSQL)
OleDbConnectionconnection=newOleDbConnection(connectionString);
OleDbDataReadermyReader=cmd.ExecuteReader();
returnmyReader;
///执行查询语句,返回DataSet
DataSet<
publicstaticDataSetQuery(stringSQLString)
DataSetds=newDataSet();
OleDbDataAdaptercommand=newOleDbDataAdapter(SQLString,connection);
command.Fill(ds,"
ds"
catch(System.Data.OleDb.OleDbExceptionex)
thrownewException(ex.Message);
returnds;
#region执行带参数的SQL语句
publicstaticintExecuteSql(stringSQLString,paramsOleDbParameter[]cmdParms)
using(OleDbCommandcmd=newOleDbCommand())
PrepareCommand(cmd,connection,null,SQLString,cmdParms);
cmd.Parameters.Clear();
SQL语句的哈希表(key为sql语句,value是该语句的OleDbParameter[])<
publicstaticvoidExecuteSqlTran(HashtableSQLStringList)
using(OleDbTransactiontrans=conn.BeginTransaction())
//循环
foreach(DictionaryEntrymyDEinSQLStringList)
stringcmdText=myDE.Key.ToString();
OleDbParameter[]cmdParms=(OleDbParameter[])myDE.Value;
PrepareCommand(cmd,conn,trans,cmdText,cmdParms);
intval=cmd.ExecuteNonQuery();
trans.Commit();
catch
trans.Rollback();
throw;
publicstaticobjectGetSingle(stringSQLString,paramsOleDbParameter[]cmdParms)
publicstaticOleDbDataReaderExecuteReader(stringSQLString,paramsOleDbParameter[]cmdParms)
publicstaticDataSetQuery(stringSQLString,paramsOleDbParameter[]cmdParms)
using(OleDbDataAdapterda=newOleDbDataAdapter(cmd))
da.Fill(ds,"
privatestaticvoidPrepareCommand(OleDbCommandcmd,OleDbConnectionconn,OleDbTransactiontran
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