Ngi thc hin: Nguyn Vn Quyt
Gii thiu tng quan v LINQ v LINQ to SQL M hnh d liu LINQ to SQL
Thao tc vi c s d liu dng LINQ to SQL LINQ to SQL v m hnh ba lp
trong lp trnh
Tng kt
Gii thiu tng quan LINQ v LINQ to SQL 1.1. Gii thiu v LINQ LINQ
chnh thc c a vo phin bn VS 2008, to ra mt bc ngot ln v mt ngn ng
cho ngnh cng ngh phn mm
Bn cht ca n chnh l thng nht s khc bit gia hai m hnh : i tng v D
liu Cng ngh h tr ng sau LINQ nh ORM (Object Relational Mapping) lm
cho vic lp trnh tr nn n gin hn, gn gng hn
Gii thiu tng quan LINQ v LINQ to SQL 1.2. LINQ l g? LINQ
Language Integrated Query: l mt tp hp cc phn m rng ca .NET
Framework, bao gm ngn ng tch hp truy vn, thip lp v chuyn i hot
ng.
LINQ c m rng trong C# v VB 9.0 vi c php ngn ng bn a cho cc truy
vn v cung cp cc th vin lp tn dng nhng kh nng thun li ca n.
Gii thiu tng quan LINQ v LINQ to SQL 1.3. Kin trc ca LINQC# 3.0
VB 9.0 Others
.NET Language-Integrated Query (LINQ)
LINQ enabled ADO.NETLINQ to Objects LINQ to Entities LINQ to SQL
LINQ to Dataset LINQ to XML
Objects
Relational Data
XML
Gii thiu tng quan v LINQ to SQL 1.4. LINQ to SQL l g? LINQ to
SQL l mt phin bn hin thc ha ca ORM (object relational mapping) c bn
trong .NET
Framework bn Orcas (nay l .NET 3.5). LINQ to SQL cho php ta m
hnh ha mt c s d liu dng cc lp .NET. Sau ta c th truy vn c s d liu
(CSDL) dng LINQ, cng nh cp nht/thm/xa d
liu t .
Gii thiu tng quan v LINQ to SQL 1.4. LINQ to SQL l g? LINQ to
SQL h tr y store procedurce, function, view v transaction. N cung
cp c ch cho lp trnh vin c th d dng kim tra tnh hp l ca d liu.
M hnh ho CSDL dng LINQ to SQL2.1. To tp
M hnh ho CSDL dng LINQ to SQL2.2. Lp DataContext Lu tr cc lp
.NET biu din cc thc th v quan h bn trong CSDL m chng ta va m hnh
ha. Mi mt file LINQ to SQL chng ta thm vo solution, mt lp
DataContext s c to ra, n s c dng khi cn truy vn hay cp nht li cc
thay i. Lp DataContext c to s c cc thuc tnh biu din mi bng c m hnh
ha t CSDL, cng nh cc phng thc cho mi SP m chng ta thm vo.
M hnh ho CSDL dng LINQ to SQL2.2. To lp m hnh d liu
M hnh ho CSDL dng LINQ to SQLLp m hnh d liu
Thao tc vi CSDL s dng LINQ to SQL 3.1. Cu trc chungTt c cc biu
thc LINQ lm vic theo ba thao tc. 1. Xc nh ngun d liu. 2. To cc truy
vn. 3. Thc hin cc truy vn.
Thao tc vi CSDL s dng LINQ to SQL 3.2. C php to truy vn from
itemName in srcExpr join itemName in srcExpr on keyExpr equals
keyExpr (into itemName)? where predExpr group selExpr by keyExpr
into itemName query-body orderby (keyExpr (ascending |
descending)?)* select selExpr
Thao tc vi CSDL s dng LINQ to SQLfrom c in db.Customers where
c.City == "London" select c.CompanyName;
Application
db.Customers.InsertOnSubmit(c1); c2.City = Seattle;
db.Customers.DeleteOnSubmit(c3);
LINQ Query
Objects
SubmitChanges()
LINQ to SQL
SQL QuerySELECT CompanyName FROM Cust WHERE City = 'London'
Rows
DML or Stored ProceduresINSERT INTO Customers UPDATE Customers
DELETE FROM Customers
SQL Server
Thao tc vi CSDL s dng LINQ to SQL 4.3. Truy vn ly d liuLINQ var
query1 = from c in db.Customers where c.City == "London" select
c;var query2 = from c in db.Customers where c.City == "London"
select new { c.CompanyName, c.Phone }; var query3 =
db.Customers.Where(c => c.City == "London); SQL
SELECT * FROM Customers WHERE City = 'London'
Thao tc vi CSDL s dng LINQ to SQL 4.4. Thm mi bn ghi vo
CSDLLINQCustomer c1 = new Customer(); c1.CustomerID = "ABCD";
c1.CompanyName = "FPT"; c1.Country = "Viet Nam"; c1.City = "Ha
Noi"; c1.Phone = "(04)38184429; db.Customers.InsertOnSubmit(c1);
db.SubmitChanges();
SQL INSERT INTO Customers(CustomerID, CompanyName, Country,
City, Phone) VALUES(ABCD,FPT,Viet Nam,Ha Noi,(04)38184429)
Thao tc vi CSDL s dng LINQ to SQL 4.5. Cp nht mi bn ghi vo
CSDLLINQCustomer cust = db.Customers.Single(c => c.CustomerID ==
"ABCD"); cust.CompanyName = FSC"; var custs = db.Customers.Where(c
=> c.Country == Viet Nam"); foreach (var c in custs) c.City = Ha
Noi"; db.SubmitChanges();
SQLUPDATE Customers SET CompanyName = FSC' WHERE
CustomerID='ABCD' UPDATE Customers SET City = 'Ha Noi' WHERE
Country = 'Viet Nam'
Thao tc vi CSDL s dng LINQ to SQL 4.6. Xo bn ghi trong
CSDLLINQCustomer cust = db.Customers.Single(c => c.CustomerID ==
"ABCD"); db.Customers.DeleteOnSubmit(cust); var custs =
db.Customers.Where(c => c.City == "Ha Noi");
db.Customers.DeleteAllOnSubmit(custs); db.SubmitChanges();
SQLDELETE Customers WHERE CustomerID == ABCDDELETE Customers
WHERE City== Ha Noi
Thao tc vi CSDL s dng LINQ to SQL 4.7. Truy vn nng caoLINQvar
result = from od in db.OrderDetails where od.Order.CustomerID ==
"ALFKI" group new { od.Product.ProductName, od.Quantity } by
od.Product.ProductName into g select new { ProductName = g.Key,
Total = g.Sum(o => o.Quantity) };
SQLSELECT ProductName, Total=SUM(Quantity) FROM Products P INNER
JOIN OrderDetails OD ON P.ProductID = OD.ProductID INNER JOIN
Orders O ON O.OrderID = OD.OrderID WHERE O.CustomerID = ALFKIGROUP
BY ProductName
Thao tc vi CSDL s dng LINQ to SQL 4.8. Mt s phng thc hay s dng
Select / SelectMany Where
Sum / Min / Max / Average / AggregateJoin / GroupJoin
GroupByTake / TakeWhile - Skip / SkipWhile OrderBy / ThenBy
First / FirstOrDefault / Last / LastOrDefault/Single
LINQ to SQL v m hnh 3 lp trong lp trnh
Tng kt
Gii thiu tng quan v LINQ v LINQ to SQLTrnh by c im, cch to v s
dng lp m hnh ho CSDL trong LINQ Cch thc lm vic vi CSDL nh truy vn,
thm, xo, sa bn ghi. nh x LINQ v m hnh 3 lp trong lp trnh
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