.NETѧϰÊÖ¼ÇÖ®£ºlinq to SQL(Ò»)
Ò»¸ö¼òµ¥µÄÀý×Ó£º
ÏȽ¨Ò»¸öC#Àࣺ
ÒýÓÃSystem.Data.Linq.dll³ÌÐò¼¯£¬
using System.Data.Linq.MappingºÍ
using System.Data.Linq Á½¸ö¿Õ¼ä¡£
[Table]
public class Inventory
{
[Column]
public string Make;
[Column]
public string Color;
[Column]
public string PetName;
//Ö¸Ã÷Ö÷¼ü¡£
[Column(IsPrimaryKey = true)]
public int CarID;
public override string ToString()
{
return string.Format(
"±àºÅ={0};ÖÆÔìÉÌ={1};ÑÕÉ«={2};°®³Æ={3}",
CarID,Make.Trim(),Color.Trim(),PetName.Trim());
}
}
ÓëSQL(express°æ)Êý¾Ý¿â½»»¥:
class Program
{
const string cnStr=
@"Data Source=(local)\SQLEXPRESS;Initial Catalog=Autolot;"+
"Integrated Security=True";
static void Main(string[] args)
{
Console.WriteLine("*****LINQ to SQL ¼òµ¥Ó¦ÓÃ*****");
//´´½¨Ò»¸öDataContext¶ÔÏó¡£
DataContext db= new DataContext(cnStr);
//´´½¨Ò»¸öTable<>·ºÐÍʵÀý¡£
Table<Inventory> invTable = db.GetTable<Inventory>();
//ÓÃÒ»¸öLINQ²éѯÏÔʾ½á¹û¡£
foreach(var car in from c in invTable select c)
Console.WriteLine(car.ToString());
}
Console.ReadLine();
}
¶ÔDataContextÀà½øÐÐÀ©Õ¹£º
class MyAutoLotDatabase:DataContext
{
public Table<Inventory> Inventory;
public MyAut
Ïà¹ØÎĵµ£º
SQLÊý¾Ý¿âÖÐÓÃimageÀ´´æ´¢Îļþ,µ«SQLûÓÐÌṩֱ½ÓµÄ´æÈ¡ÎļþµÄÃüÁî.
/*--bcp ʵÏÖ¶þ½øÖÆÎļþµÄµ¼Èëµ¼³ö
Ö§³Öimage,text,ntext×ֶεĵ¼Èë/µ¼³ö
imageÊʺÏÓÚ¶þ½øÖÆÎļþ,°üÀ¨:WordÎĵµ,ExcelÎĵµ,ͼƬ,ÒôÀÖµÈ
text,ntextÊʺÏÓÚÎı¾Êý¾ÝÎļþ
×¢Òâ:µ¼Èëʱ,½«¸²¸ÇÂú×ãÌõ¼þµÄËùÓÐÐÐ
µ¼³öʱ,½ ......
Çë½Ì´ó¼ÒÒ»¸öÓйØSQL½»×¤±¨±í²éѯÎÊÌ⣬»¶Ó¸÷λָ½Ì£¡
ÎÒÏë°Ñͼ1µÄʹÓÃÐÅÏ¢£¬Ê¹ÓÃSQLÓï¾ä£¬ÊµÏÖÈçͼ2µÄ½á¹û¡£
±íÃû
ÐòºÅ
×Ö¶ÎÃû
a
1
c
a
2
d
a
3
e
a
4
f
a
5
g
b
1
h
b
2
i
b
3
j
b
4
k
b
5
l
c
1
m
c
2
n
c
3
o
c
4
p
c
5
q
ͼ1
±íÃû
ÐòºÅ
1
2
3
4
5
......
Ò»¡¢Ê¹ÓÃSqlConnection¶ÔÏóÁ¬½ÓSQL ServerÊý¾Ý¿â
1¡¢µÇ¼Êý¾Ý¿âµÄ·½Ê½ÎªSQL ServerÑé֤ģʽ
server=·þÎñÆ÷Ãû;database=Êý¾Ý¿âÃû³Æ;uid=Óû§;pwd=ÃÜÂë
2¡¢µÇ¼Êý¾Ý¿âµÄ·½Ê½ÎªWindowsÑé֤ģʽ
server=·þÎñÆ÷Ãû;database=Êý¾Ý¿âÃû³Æ;Integrated Security=SSPI
ÆäÖУ¬Integrated Security¼´Trusted_Connection,È¡Ö ......
sql isnullº¯ÊýµÄʹÓÃ
ISNULL
ʹÓÃÖ¸¶¨µÄÌæ»»ÖµÌæ»» NULL¡£
Óï·¨
ISNULL ( check_expression , replacement_value )
²ÎÊý
check_expression
½«±»¼ì²éÊÇ·ñΪ NULLµÄ±í´ïʽ¡£check_expression ¿ÉÒÔÊÇÈκÎÀàÐ͵ġ£
replacement_value
ÔÚ check_expression Ϊ NULLʱ½«·µ»ØµÄ±í´ïʽ¡£replacement_value ±ØÐëÓë chec ......
¾¡Á¿ÉÙÓÃIN²Ù×÷·û£¬»ù±¾ÉÏËùÓеÄIN²Ù×÷·û¶¼¿ÉÒÔÓÃEXISTS´úÌæ¡£
²»ÓÃNOT IN²Ù×÷·û£¬¿ÉÒÔÓÃNOT EXISTS»òÕßÍâÁ¬½Ó+Ìæ´ú¡£
OracleÔÚÖ´ÐÐIN×Ó²éѯʱ£¬Ê×ÏÈÖ´ÐÐ×Ó²éѯ£¬½«²éѯ½á¹û·ÅÈëÁÙʱ±íÔÙÖ´ÐÐÖ÷²éѯ¡£¶øEXISTÔòÊÇÊ×Ïȼì²éÖ÷²éѯ£¬È»ºóÔËÐÐ×Ó²éѯֱµ½ÕÒµ½µÚÒ»¸öÆ¥ÅäÏî¡£NOT EXISTS±ÈNOT INЧÂÊÉԸߡ£µ«¾ßÌåÔÚÑ¡ÔñIN»òEXIST² ......