1、添加引用

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using System.Data.SqlClient;
2、建立連接調(diào)用
SqlConnection?myConnection?=?new?SqlConnection("數(shù)據(jù)庫(kù)連接字符串");
//數(shù)據(jù)庫(kù)連接字符串通常是Data?Source=localhost;Initial?Catalog=數(shù)據(jù)庫(kù)名;User?ID=用戶名;Password=密碼
SqlCommand?myCommand?=?new?SqlCommand();
myCommand.CommandText?=?string.Format("select?count(*)?from?{0}?where?columName={1}",表明,列值);//構(gòu)造SQL查詢語(yǔ)句?????String.Format?(String,?Object[])?將指定?String?中的格式項(xiàng)替換為指定數(shù)組中相應(yīng)?Object?實(shí)例的值的文本等效項(xiàng)。????????myCommand.Connection?=?myConnection;
try
{
myCommand.Connection.Open();
int?count?=?(int)myCommand.ExecuteScalar();
if?(count??0)???
{
//count大于0表示有,調(diào)用自己寫的一個(gè)方法來(lái)更新
UpdateData();
}
else
{
小于0表示沒有,調(diào)用這個(gè)方法來(lái)插入????????????
InsertData();
}
}
catch?(Exception?ex)
{
Response.Write(ex.ToString());
}
//UpdateData方法????
public?void?UpdateData()
{
SqlConnection?myConnection?=?new?SqlConnection("數(shù)據(jù)庫(kù)連接字符串");
SqlCommand?myCommand?=?new?SqlCommand();
myCommand.CommandText?=?"用來(lái)更新的SQL語(yǔ)句";
myCommand.Connection?=?myConnection;
try
{
myCommand.Connection.Open();
myCommand.ExecuteNonQuery();
}
catch?(Exception?ex)
{
Response.Write(ex.ToString());
}
}
//InsertData方法?
public?void?InsertData()
{
SqlConnection?myConnection?=?new?SqlConnection("數(shù)據(jù)庫(kù)連接字符串");
SqlCommand?myCommand?=?new?SqlCommand();
myCommand.CommandText?=?"用來(lái)插入的SQL語(yǔ)句";
myCommand.Connection?=?myConnection;
try
{
myCommand.Connection.Open();
myCommand.ExecuteNonQuery();
}
catch?(Exception?ex)
{
Response.Write(ex.ToString());
}
}
-----這些都是基礎(chǔ)的寫法,可以將其封裝在一個(gè)工具類中,方便調(diào)用。
using?System;
using?System.Collections.Generic;
using?System.Linq;
using?System.Text;
using?System.Configuration;
using?System.Data;
using?System.Data.SqlClient;
namespace?DBUtility
{
public?class?SqlHelper
{
//通過(guò)配置文件(app.config:xml)讀取連接字符串
public?static?string?connectionString?=?ConfigurationManager?.ConnectionStrings["ConnectionString"].ConnectionString;
//字段,通過(guò)連接字符串獲取連接對(duì)象
private?SqlConnection?con?=?new?SqlConnection(connectionString);
//屬性,判斷連接對(duì)象的狀態(tài)并打開連接對(duì)象
public?SqlConnection?Con
{
get?{
switch?(con.State)
{
case?ConnectionState.Broken:
con.Close();?//先正常關(guān)閉,釋放資源
con.Open();
break;
case?ConnectionState.Closed:
con.Open();
break;
case?ConnectionState.Connecting:
break;
case?ConnectionState.Executing:
break;
case?ConnectionState.Fetching:
break;
case?ConnectionState.Open:
break;
default:
break;
}
return?con;?}
set?{?con?=?value;?}
}
//執(zhí)行存儲(chǔ)過(guò)程或者SQL語(yǔ)句并返回?cái)?shù)據(jù)集DataSet
public?DataSet?GetDataSet(string?strSQL,?CommandType?cmdType,?params?SqlParameter[]?values)
{
SqlCommand?cmd?=?PrepareCommand(strSQL,?cmdType,?values);
SqlDataAdapter?da?=?new?SqlDataAdapter(cmd);
DataSet?ds?=?new?DataSet();
da.Fill(ds);
return?ds;
}
//執(zhí)行存儲(chǔ)過(guò)程或者SQL語(yǔ)句并返回SqlDatareader
public?SqlDataReader?GetDataReader(string?strSQL,?CommandType?cmdType,?params?SqlParameter[]?values)
{
SqlCommand?cmd?=?PrepareCommand(strSQL,?cmdType,?values);
SqlDataReader?dr?=?cmd.ExecuteReader(CommandBehavior.CloseConnection);
return?dr;
}
//執(zhí)行存儲(chǔ)過(guò)程或者SQL語(yǔ)句并返回首行首列(新增方法的主鍵)
public?object?ExecuteScalar(string?strSQL,?CommandType?cmdType,?params?SqlParameter[]?values)
{
SqlCommand?cmd?=?PrepareCommand(strSQL,?cmdType,?values);
return?cmd.ExecuteScalar();
}
//執(zhí)行存儲(chǔ)過(guò)程或者SQL語(yǔ)句并返回受影響行數(shù)
public?int?ExecuteNonQuery(string?strSQL,?CommandType?cmdType,?params?SqlParameter[]?values)
{
SqlCommand?cmd?=?PrepareCommand(strSQL,?cmdType,?values);
return?cmd.ExecuteNonQuery();
}
//內(nèi)部方法,實(shí)例化命令對(duì)象并配置相關(guān)屬性
private?SqlCommand?PrepareCommand(string?strSQL,?CommandType?cmdType,params?SqlParameter[]?values)
{
SqlCommand?cmd?=?new?SqlCommand();
cmd.Connection?=?Con;
cmd.CommandText?=?strSQL;
cmd.CommandType?=?cmdType;
cmd.CommandTimeout?=?60;
cmd.Parameters.AddRange(values);
return?cmd;
}
}
}
using System.Data.SqlClient;
using System.Data;
SqlConnection SqlCon=new SqlConnection("server =服務(wù)器;database =數(shù)據(jù)庫(kù);uid =帳號(hào);pwd =密碼");
public static DataTable GetTable(string select)
{
try
{
SqlDataAdapter da = new SqlDataAdapter(select, SqlCon);
DataTable dt = new DataTable();
da.Fill(dt);
return dt;
}
catch (Exception ex)
{
throw ex;
}
}
其中select 一般形式是 "select * from table"
樓主你好:
你可以使用下面這個(gè)語(yǔ)句查詢出你想要表的字段類型、長(zhǎng)度等信息。
Column_name是你的表字段信息,
Type_name是你該字段的數(shù)據(jù)類型,
Type_length是該數(shù)據(jù)類型的默認(rèn)長(zhǎng)度,
Column_lengh是該數(shù)據(jù)類型的實(shí)際長(zhǎng)度,這個(gè)字段的值就是你想要的數(shù)據(jù)
SELECT dbo.sysobjects.name as Table_name,
dbo.syscolumns.name as Column_name,
dbo.systypes.name as Type_name,
dbo.systypes.length as Type_length,
columnproperty(dbo.syscolumns.id,dbo.syscolumns.name,'precision') as Column_lengh
from dbo.syscolumns inner join dbo.sysobjects
on dbo.syscolumns.id = dbo.sysobjects.id
left join dbo.systypes
on dbo.syscolumns.xtype = dbo.systypes.xusertypewhere dbo.sysobjects.name = '你的表名'
and AND dbo.syscolumns.name='你想查詢的字段名稱'
你在C#中執(zhí)行這個(gè)語(yǔ)句,傳入你想要的條件,得到的結(jié)果就是你想要的東西,
或者使用SELECT name,length FROM SYSCOLUMNS WHERE ID=OBJECT_ID('表名' ) where name='字段名'
希望對(duì)你有幫主,望采納:)謝謝
返回的時(shí)候用dataset就可以,比如你存儲(chǔ)過(guò)程這樣寫
select * from A
select * from B
select * from C
select * from D
select * from D
在執(zhí)行完存儲(chǔ)過(guò)程后返回一個(gè)dataset
dataset ds = 執(zhí)行存儲(chǔ)過(guò)程
ds.tables[0]就是表A
ds.tables[1]就是表B
ds.tables[2]就是表C
剩下的依次類推.
using (SqlConnection cn = new SqlConnection("Data Source=(local);Initial Catalog=xxx;User ID=sa;Password=sa"))
{
try
{
cn.Open();
SqlCommand cmd = new SqlCommand();
cmd.Connection = cn;
cmd.CommandText = "select * from tablename";
SqlDataReader dr = cmd.ExecuteReader();
while (dr.Read())
{
...
}
dr.Close();
dr=null;
}
catch
{
MessageBox.Show("連接數(shù)據(jù)庫(kù)失敗!");
}
}
1、確定目標(biāo)Sqlserver是否允許遠(yuǎn)程訪問
2、確定目標(biāo)SqlServer服務(wù)端口是否是默認(rèn)端口
3、檢查數(shù)據(jù)庫(kù)名稱、密碼什么是否正確
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