Comparing and Contrasting C Scheme and TSQL Joseph

Comparing and Contrasting C#, Scheme, and T-SQL Joseph P. Mohr

Outline 1. 2. 3. 4. 5. C# Overview Scheme Overview T-SQL Overview Language Comparisons Conclusions

C# Overview � Object-Oriented � Type-Safe � Evolved Language from C � Main application is server-side scripting in the. NET Framework � Developed in 2001 � Current version is 4. 0

C# Advantages � C# is designed for component-oriented programming � Software Components ◦ Increasingly used in modern software design ◦ Self-contained and self-describing ◦ Have their own documentation

C# Advantages � Versioning ◦ Allows the language to evolve without breaking programs in older versions. ◦ Supports virtual and override modifiers. ◦ Method overloading that supports versioning. ◦ Explicit interface member declarations.

C# Advantages � Virtual and Override ◦ If a method is declared virtual, then the implementation evokes is determined at run-time. ◦ Non-Virtual methods have the implementation determined at compile-time. ◦ The override modifier can be used to provide another implementation for an existing virtual method.

C# Program Structure � C# ◦ ◦ ◦ programs are comprised of the following: Programs Namespaces Types Members Assemblies

C# Programs � Consist of one or more source files � Source files contain the other structural elements of the program

C# Namespaces � Declared at the top of the source file with the using directive � Avoid having to use the fully qualified names in the source code.

C# Types � Most common types: ◦ Classes ◦ Interfaces � Can contain members and namespaces � Either reference or value � With reference type, two variables can affect the same object.

C# Members � Most ◦ ◦ common members: Fields Methods Properties Events

C# Assemblies � Made up of Intermediate Language (IL) and metadata � Use Just-In-Time (JIT) compiling � Implement applications or libraries and have the. exe or. dll file extension respectively

C# Hello World Program Using System; Class Hello { Static void Main() { } } Console. Out. Write. Line(“Hello, World”);

C# Grammars � C# uses two different grammars, the Lexical grammar and the syntactic grammar. � Lexical grammar defines line terminators, white space, comments, tokens, and preprocessing directives. � Syntactic grammar defines how the tokens from the lexical grammar are combined into programs.

C# Performance � Compiled language results in fast execution. � High performance is a result of being derived from the C family. � Boxing and Unboxing operations are the most common detriments to performance. ◦ Can be avoided by declaring as Object

C# Readability � Pros: ◦ Clearly defined data types ◦ Familiar, well designed syntax � Cons: ◦ Feature multiplicity ◦ Operator Overloading

C# Writability � Pros: ◦ Excellent support for abstraction ◦ Strong expressivity with control sections � Cons: ◦ Large number of different contstructs

C# Orthogonality � Classes derived from the base Object Class, which includes implementation of the primitives, can be simply combined to create very robust and diverse data structures.

C# Reliability Pros � Type-Checking: ◦ C# is considered a type-safe language and the compiler can catch type errors in almost all cases. ◦ There are pointers supported by the language which can prevent the compiler from catching type-errors. � Exception Handling: ◦ Highly functional and similar to Java

C# Reliability Cons � Aliasing: ◦ Reference types can be referring to the same memory location and is considered a detriment to reliability.

C# Portability � The modular design considerations of C# makes the code highly portable. � Self-contained documentation in all the modules makes for easier portability amongst different software developers.

C# Tools and Compilers � MS Visual C# � MS Visual Studio

C# Personal Example using using System; System. Collections. Generic; System. Linq; System. Web. UI; System. Web. UI. Web. Controls; namespace Web. Application 2 { public partial class _Default : System. Web. UI. Page { protected void Page_Load(object sender, Event. Args e) { } protected void Calendar 1_Day. Render(object sender, Day. Render. Event. Args e) { Event. Data. Context edc = new Event. Data. Context(); var query = from ev in edc. Events where ev. Date == e. Day. Date select ev;

C# Personal Example Contd. e. Cell. Vertical. Align = Vertical. Align. Top; e. Cell. Border. Color = System. Drawing. Color. Teal; e. Cell. Border. Width = 1; e. Cell. Border. Style = Border. Style. Solid; } } } foreach (var ev in query) { Hyper. Link link = new Hyper. Link(); link. Fore. Color = System. Drawing. Color. Teal; link. Navigate. Url = "~/Event. Info. aspx? event=" + ev. Event. No; link. Text = ev. Name; Button but = new Button(); e. Cell. Controls. Add(new Literal. Control("<p>")); e. Cell. Controls. Add(link); e. Cell. Controls. Add(new Literal. Control("</p>")); }

C# Demo � www. myjaxcalendar. com

Scheme Overview � Functional programming language � Evolved from LISP � Created in 1975 at MIT by Guy L. Steele and Gerald J. Sussman � Originally called Schemer to mimic the naming convention used by other languages evolved from LISP, such as Conniver � Considerably more minimalist than Common Lisp, but supports tools for language extension.

Scheme Applications � Most commonly used for lambda calculus and as an educational tool by introductory level computer science classes. � Lambda calculus is a logical system of computation through the use of binding and substitution.

Scheme Programs � Scheme programs are interpreted. � Program Elements: Keywords Variables Structured forms Constant data (numbers, characters, strings, quoted vectors, quoted lists, quoted symbols, etc. ) ◦ Whitespace ◦ Comments ◦ ◦ � Program expressions are known as sexpressions

Scheme Syntax � S-expressions are made up of structured forms and lists. � S-expressions are delineated by matching sets of opening and closing parentheses.

Scheme Primitives and Variables � List-processing primitives: ◦ car – the first element in a list ◦ cdr – all the other elements in the list ◦ cons – constructs lists � First-class functions (functions can be assigned to variables)

Scheme Variable Scoping � Only the inner-most binding of a variable is visible in an expression. � Inner bindings are said to “shadow” the outer bindings. � This type of scoping is known as “lexical scoping”.

Scheme Example Expression � Expression: ◦ (cdr (car ‘((1 2 3) 4 5))) � Result: ◦ (2 3)

Scheme Performance � Scheme executes faster and more efficiently than Common LISP as a result of its minimalist design.

Scheme Readability � Pros: ◦ Overall Simplicity of the language, including a lack of feature multiplicity, improves the readability of the language. ◦ Identifiers are not restricted in length. � Cons: ◦ The dynamic variable types which aren’t explicitly declared to be of a certain data type.

Scheme Writability � Pros: ◦ The overall simplicity of the language, especially over that of Common LISP � Cons: ◦ Weak support for abstraction ◦ Lacking expressivity

Scheme Orthogonality � Simply supports the most commonly used data structures including Strings and Enums. � Lacking in the ability to combine primitives in to complex data structures.

Scheme Reliability � Pros: ◦ Lack of aliasing ◦ Performs run-time type checking � Cons: ◦ Does not have a good system for exception handling.

Scheme Portability � Scheme programs are highly portable between the same version of Scheme. � The very high number of versions of Scheme in use is major stumbling block to the portability of Scheme.

Scheme Flavors � Some of the many flavors of scheme are: ◦ SISC – runs off of the JVM ◦ Dr. Racket – Student friendly interface ◦ MIT Scheme – very widely used

Scheme Demo

T-SQL Overview � Query Language � Uses statements that are interpreted by the database server. � Used with relational databases ◦ Relational databases are based off of first order predicate logic. � Used by MS SQL Server database and Sybase database. � Main application is the construction and manipulation of enterprise databases.

T-SQL Overview � History: ◦ Evolved from SEQUEL. ◦ SEQUEL (Structured English Query Language) is a query language developed by IBM in the 1970’s and they later renamed it to SQL (Structured Query Language) ◦ T-SQL (Transact SQL) is an extension to SQL developed by a partnership between Microsoft and Sybase.

T-SQL Overview � Data in relational databases are comprised of entity types � Entity Types are collections of the entities and thought type and are represented as TABLES. � Each instance of that entity is a record or tuple and is represented as a row in the table. � Records are comprised of different attributes, and they are represented as columns in the table.

T-SQL Overview � T-SQL is technically a data-sublanguage � The T-SQL sublanguage is comprised of the following: ◦ Data Definition Language (DDL) ◦ Data Manipulation Language (DML)

T-SQL DML � The DML is used to define database structure, integrity rules, and user privileges. � Includes the following commands: ◦ CREATE TABLE, DROP TABLE, ALTER TABLE ◦ CREATE VIEW, DROP VIEW ◦ CREATE INDEX, DROP INDEX

T-SQL DML � The DML is used to manipulate the data within the database. � DML Commands Include: ◦ ◦ SELECT INSERT UPDATE DELETE

T-SQL Extensions � T-SQL extends SQL to include: ◦ Procedural Programming ◦ Local Variables ◦ Support functions for processing various data types � The extensions included in T-SQL grant it equivalent capabilities to other programming languages.

T-SQL Extensions � Flow ◦ ◦ ◦ ◦ ◦ control in T-SQL: Begin End Break Continue GOTO IF ELSE RETURN WHILE WAITFOR

T-SQL Exception Handling � T-SQL contains try-catch blocks, unlike SQL � Example: BEGIN TRY //STATEMENTS END TRY BEGIN CATCH //STATEMENTS TO HANDLE EXCEPTION END CATCH

T-SQL Demo

T-SQL Efficiency � T-SQL performs queries and data manipulation very efficiently across a wide variety of data types.

T-SQL Simplicity � Readability: ◦ High overall simplicity. Lack of multiplicity and overloading. ◦ Excellent facilities for defining data types ◦ Form indicates meaning � Writability: ◦ More expressive than SQL ◦ Poor Abstraction

T-SQL Orthogonality � T-SQL supports a wide variety of primitive data types � The primitive data types can be easily combined in tables to easily create new data structures.

T-SQL Reliability � Type-Checking: ◦ Data must be of the appropriate type for a statement to execute. � Exception-Handling: ◦ T-SQL provides for exception handling, unlike SQL.

Language Comparisons � Modularity and portability are a common and touted attribute amongst the languages, but C# achieves this goal to a greater extent than the others. � C# does not support shadowing like Scheme does. � All three languages are supported crossplatform.

Concluding Remarks �I drew the following conclusions my research in to these three languages: ◦ Studying different types of languages increased my ability to select an appropriate language for a given task. ◦ As I learned more languages, I was able to pick up new languages faster. ◦ Due to the similarities between the languages, studying C# improved my knowledge of Java. ◦ Many projects are best implemented through the use of multiple languages.