Microsoft SQL Serveris arelational database server, developed by Microsoft. It is a software product whose primary function is to store and retrieve

Transcription

1 SS Chung

2 Microsoft SQL Serveris arelational database server, developed by Microsoft. It is a software product whose primary function is to store and retrieve data as requested by other software applications. Transact SQL (T-SQL) as primary query language Includes: SQL DDL, SQL DML Variables Assignment Iteration Procedures Functions Triggers

3 .NET is developed bymicrosoft..net Frameworkis asoftware frameworkthat runs primarily onmicrosoft Windows and includes a largelibraryand provides language interoperability across several programming languages..net Platform.NET runtime - Common Language Runtime (CLR) Verifiable Intermediate Language Managed memory garbage collection Multiple languages (e.g, C#, C++, Cobol) Frameworks library (e.g., GUI, Files, XML) Assemblies New Dynamic Link Libraries Contain code + metadata (class definitions, assembly dependencies) Unit of code deployment, security, versioning

4 Running application code inside the database in a reliable, secure, scalable and efficient manner for applications that require complex business logic. Data volumes are exploding from Terabytes to Petabytes and Exabytes. Cannot afford the cost of shipping data Why move something heavy?

5 Broaden the set of languages for running data-intensive business logic in server IT Developers and ISVs Multiple languages: Visual Basic, C#, C++, J#, Same mid- and server-tier data access model Same tools: IDE, project model, debugging, Transact-SQL still supported Packaged as.net assemblies Verifiable, secure Deployed to SQL Server as Functions, procedures, triggers, types Basis for SQL Server Extensibility

6 In the.net framework, many different high-level programming languages can be used to construct programs. The compilation of the program produces Assembly - compiled code in Microsoft Intermediate Language (MSIL) Manifest - contains all references to dependent assemblies The Manifest contains - Assembly s metadata Structures Fields Properties Classes Inheritance relationships Functions And methods defines in assembly

7 CLR Routines mapped to public, static, annotated methods of a class. Classes compiled into DLL of MSIL and run on the CLR. In Java, MSIL(= Byte code), CLR (=JVM) Managed code is MSIL executed in CLR (Rather than OS) Converted to machine code at run time Just in Time (JIT) compiler translates MSIL to native code.

8 Managed code applications gain CLR services: Garbage collection Runtime type checking Security support These services provide language independent behavior. Just in Time (JIT) compiler translates MSIL to native code. SQL Server and CLR manage system resource including: Memory management Synchronization primitives Thread scheduling SQL Server acts as OS for CLR when it is hosted inside SQL Server process. It encapsulates all OS primitives in a component called SQL OS.

9 Hosting common language runtime inside SQL Server Safety, security, scalability, speed Run verified, type-safe code inside process Multiple languages Data access in process Based on ADO.NET Same data access programming model as middle-tier SQLTypes SQL type semantics in managed code

10 Server-side programming environment for: User Defined Functions, Stored Procedures, Triggers User Defined Types, user defined Aggregates In-Proc Data Access (ADO.NET) Common ADO.NET Programming Model Both Mid-tier/data tier Security Integration of SQL and CLR security Three levels of code access security Safe, External-Access (verifiable), Unsafe Tight integration with Visual Studio Authoring, debugging, deployment, & profiling

11 VB,C#,C++ VS.NET Project Build Assembly: TaxLib.dll 11 Runtime hosted by SQL (in-proc) SQL Queries: select sum(tax(sal,state))from Emp where county = King SQL Server SQL Data Definition: create assembly create function create procedure create trigger create type

12 CLR user-defined functions (UDFs) provide a mechanism for extending SQL Server with new scalar and table-valued routines written in.net languages A static method can be registered as a scalar CLR UDF. For example, A new function for a mathematical or statistical operation not natively supported by SQL Server can be written as static function in C# and registered as a CLR UDF. CLR UDFs also allow SQL Server to leverage the functionality available in.net framework Libraries for compression (System.IO.Compression), regular expressions (System.Text.RegularExpressions), and cryptography (System.Security.Cryptography) can all be used inside CLR UDFs.

13 Scalar Functions Table-Valued Functions (TVF) CLR allows for parallel executing on functions (T- SQL does not) CLR outperforms T-SQL Important Points of Functions Can accept parameters Are embedded within a TSQL statements

14 Table-Valued Function SELECT* FROM dbo.employee e JOIN dbo.myfunction() f ON e.empid = f.empid ORDER BY e.lname Scalar Function SELECT*,dbo.addTax(totalprice)TaxIncluded FROM dbo.sales ORDER BY TaxIncluded DESC

15 CLR TVFs provide a mechanism for converting raw data into a relation CLR TVFs uses a pull model to stream the data into relation SQL Server requests and processes one row of data from the CLR TVF at a time and then the entire relation is being processed T-SQL TVFs use Push model which materializes the entire relation before it can be processes by SQL Server CLR TVFs that use Pull model which streams the data into relation: Convert text to a relation SQL Server pulls 1 row at a time (as opposed to whole relation.) That way it can start processing results immediately

16 CLR TVF itself is a class implementing the IEnumerator interface. IEnumerator decomposes the SqlBytes parameter into rows Current() MoveNext() Reset()

17 CLR TVFs provide a mechanism for converting raw data into a relation The procedural constructs of T-SQL language are not as rich as those of the CLR. T-SQL is an interpreted language and the CLR languages are compiled to MSIL and JITed to machine instructions. T-SQL UDFs prevent a query from executing in parallel where as CLR UDFs are parallelizable, and thus achieve better performance on multiprocessor systems.

18 CLR UDFs can be written in any CLR supported language, T-SQL UDFs are restricted to T-SQL language. The procedural constructs of T-SQL language are not as rich as those of the CLR. T-SQL is an interpreted language and the CLR languages are compiled to MSIL and JITed to machine instructions. T-SQL UDFs prevent a query from executing in parallel where as CLR UDFs are parallelizable, and thus achieve better performance on multiprocessor systems.

19 T-SQL TVFs use a push model which materializes the entire relation before it can be processes by SQL Server where as the pull model used by CLR TVFs give them a better performance for returning smaller sized relations. CLR TVFs provides a customizable and flexible interface for data import operations. T-SQL is restricted to the APIs provided by a series of INSET statements.

20 Init method -returns IEnumerable IEnumerator implementation -decomposes SQL bytes into rows Fill row method -decodes objects from IEnumerable to produce individual columns

21 SELECT TOP 10 * FROM dbo.initmethod ('System') ORDER BY timewritten;

22 CREATE FUNCTION [nvarchar](4000)) RETURNS TABLE ( [timewritten] [datetime] NULL, [message] [nvarchar](max) NULL, [category] [nvarchar](4000) NULL, [instanceid] [bigint] NULL ) WITH EXECUTE AS CALLERORDER ([timewritten]) AS EXTERNAL NAME [SqlServerProject1].[Tabular EventLog].[InitMethod]

23 Can create UDTs in both SQL Server and CLR Good for Simple objects like a Point (latitude/longitude) Bad for Complex objects like Employee or Company

24 SQL Server introduced user-defined types as a mechanism to extend the scalar type system of SQL SQL Server UDTs, implemented as CLR classes or structs, are designed to model specialized date or time, spacial types etc. CLR UDTs are CLR classes with some additional restrictions They can be instantiated on a managed client as well as in the server

25 Example Point Serialization Accessing Members Sorting Conversion Nullability

26 Serialization -To persistently store on disk Native serialization -only primitive types User-defined serialization -implement IBinarySerialize interface to remove type restriction Sorting and Indexing -How to sort UDT? By declaring type as byte ordered Nullability -Type must implement properties IsNull -true for null instances Null -provides null instance

27 Hierarchyid Geography Geometry

28 GPS Needs to store coordinates CREATE TABLE points_of_sale (id int, name nvarchar(50), location geography); INSERT INTO points_of_sale(id, name, location) VALUES (1000, N Main Store, geometry::stpointfromtext('point ( )', 4326)); SELECT id, name FROM points_of_sale WHERE location.stintersects (@urban_area) = 1;

29 Hierarchyid built in type built on UDT

30 Limitations Inheritance is not supported Overloaded methods cannot be called Static data members must be read-only Migration from CLR data type

31 User-Defined Aggregates Commission Commission is broken into: 4% of software sales 2% of services revenue Problem: Show each sales rep and their total commission since 01/01/2013

32 Contract Init() Accumulate() Merge() Terminate()

33 Aggregate functions perform a calculation on a set of values and return a single value. CLR UDAs give users the ability to write their own aggregates to suite their own specific needs. Some common applications include: String processing Statistical computations Mathematical computations CLR UDAs are tightly integrated into the system, in the same manner as native aggregates and can be parallelized by the system.

34 Examples of ROUTINES: Stored procedures Table valued fucntions Traditionally, data access from.net routines is done via ADO.NET SqlClient interfaces. Microsoft has introduced a new Language Integrated Query (LINQ) technologies that extend.net languages natively with query expressions to further reduce and completely eliminate impedance mismatchof applications.

35 Example Code: public class StudentClass { #region data protected enum GradLevel { FirstYear = 1, SecondYear, ThirdYear, FourthYear }; protected class Student { public string FirstName { get; set; } public string LastName { get; set; } public int ID { get; set; } public GradLevel Year; public List<int> ExamScores; } protected static List<Student> students = new List<Student> { new Student {FirstName = "Terry", LastName = "Adams", ID = 120, Year = GradLevel.SecondYear, ExamScores = new List<int>{ 99, 82, 81, 79}}, new Student {FirstName = "Fadi", LastName = "Fakhouri", ID = 116, Year = GradLevel.ThirdYear, ExamScores = new List<int>{ 99, 86, 90, 94}}, new Student {FirstName = "Hanying", LastName = "Feng", ID = 117, Year = GradLevel.FirstYear, ExamScores = new List<int>{ 93, 92, 80, 87}} }

36 CREATE TABLE Employees( EmpId int primary key, Name varchar(100), varchar(100), Phone varchar(10), Title varchar(20), HireDate date);

37 [Microsoft.SqlServer.Server.SqlFunction( FillRowMethodName = "FillEmpRdr", DataAccess = DataAccessKind.Read, TableDefinition = "hiredate DATETIME, Name NVARCHAR(100)")] public static Ienumerable EmpsByDate(DateTime date) { using( SqlConnection con = new SqlConnection(CONN_STRING) ) { con.open(); SqlCommand cmd = con.createcommand(); cmd.commandtext SELECT HireDate, Name FROM Employees e WHERE e.hiredate cmd.parameters.addwithvalue("@date",date); return cmd.executereader().getenumerator(); } } public static void FillEmpRdr( Object o, out datetime hiredate, out string name){ name = (datetime)((idatarecord)o)["hiredate"]; city = (string)((idatarecord)o)["name"]; }

38 [Microsoft.SqlServer.Server.SqlFunction( DataAccess = DataAccessKind.Read] public static IQueryable<Employee> EmpsByDate(DateTime date) { using (EmpDBdb = new EmpDB()) { varemps= from e in db.employees where e.hiredate < date select e; return emps; } }

39 Compile type checking of query expressions Elimination of FillEmpRdr() routine by using generic collection types The amount of information that needs to be specified inside the SqlFunction custom attribute is reduced. LINQ can be used to express data access request inside routines.