What is Programming Language?• A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer.• Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely
Mark-up Language• A mark-up language is a modern system for annotating a document in a way that is syntactically distinguishable from the text.• The idea and terminology evolved from the "marking up" of manuscripts,
HTML (Hypertext Make- up Language)• HTML is a language for creating Web page. The term markup language comes from the books publishing industry. Before a book is type-set and printed, a copy editor reads the manuscript and puts mark on it. These marks tell the compositor how to format the text .
HTML is a language for describing web page.• HTML stands for Hyper Text Markup Language.• HTML is not a programming language, it is a markup language.• A markup language is a set of markup tags.• HTML uses markup tags to describe web pages.
HTML Tags• HTML tags are keywords surrounded by angle brackets like <html>.• HTML tags normally come in pairs like <b> and </b>.• The first tag in a pair is the start tag, the second tag is the end tag.• Start and end tags are also called opening tags and closing tags
Boldface Tags• The two tags <B> and </B> are instructions for the browser. When the browser sees these two marks, it knows that the text must be boldface.
Beginning and ending tags• The beginning tag can have attributes and values and starts with the name of the tag. The ending tag cannot have attributes or values but must have a slash before the name of the tag.
Example of small section of text marked up in HTML<h1> Anatidae </h1> <p>The family <i>Anatidae</i> includesducks, geese, and swans, but<em>not</em> the closely relatedscreamers.</p>
XML (Extensible Mark- up Language )• Is a meta mark-up language that is now widely used. XML was developed by the World Wide Web Consortium, in a committee created and chaired by Jon Bosak.• XML remains a meta-language like SGML, allowing users to create any tags needed (hence "extensible") and then describing those tags and their permitted
XHTML (Extensible Hypertext Mark up Language)• The language specification requires that XHTML Web documents must be well-formed XML documents – this allows for more rigorous and robust documents while using tags familiar from HTML.
Elements• Syntax A programming languages surfaceform is known as its syntax. Mostprogramming languages are purely textual;they use sequences of text including words,numbers, and punctuation, much likewritten natural languages.
Elements• Programming • expression ::= atom | language syntax is list atom ::= number | usually defined using symbol number ::= [+- a combination of ]?[0-9]+ symbol ::= regular expressions [A-Za-z].* list ::= ( (for lexical structure) expression* ) and Backus–Naur Form (for grammatical structure). Below is a simple grammar, based on Lisp:
This grammar specifies the following:• an expression is either an atom or a list;• an atom is either a number or a symbol;• a number is an unbroken sequence of one or more decimal digits, optionally preceded by a plus or minus sign;• a symbol is a letter followed by zero or more of any characters (excluding whitespace); and• a list is a matched pair of parentheses, with zero or more expressions inside it.
Semantics• The term Semantics refers to the meaning of languages, as opposed to their form (syntax).
Static Semantics• The static semantics defines restrictions on the structure of valid texts that are hard or impossible to express in standard syntactic formalisms.• For compiled languages, static semantics essentially include those semantic rules that can be checked at compile time.
Dynamic Semantics• Once data has been specified, the machine must be instructed to perform operations on the data• The dynamic semantics (also known as execution semantics) of a language defines how and when the various constructs of a language should produce a program behavior.
File Organization Terms and Concepts Character- consists of a single alphabetic, numeric or other symbol Field- a grouping of character into a word, a group of words, or a complete number, such as a person’s name or age Record- a group of related fields File- a group of records of the same type Database- a group of logically related files or object
Entity- a person, place, things or event about which information must be kept Attribute- a piece of information describing particular entity Key Field- a field in a record that uniquely identifies instances of that record so that it can be retrieved, updated or sorted. Query- is a statement you define, which tells the DBMS to find records that match criteria you specify Tuple- a row or record in a relational database
Problems with Traditional File Management SystemData redundancyPrograms data-dependenceLack of flexibilityPoor securityLack of data-sharing and availability
The Database Management ApproachConsolidates data records and objects into databases that can be accessed by many different application programs.
DATABASE• It is a collection of data organized to serve many applications efficiently by centralizing the data and minimizing redundant data.
DBMS (Database Management System)It is a special software or computerprograms that control thecreation, maintenance and use of databaseof an organization and its end users.DBMS 3 Components:A data definition languageA data manipulating languageA data dictionary
Operational DatabasesOperational Databases are very important to abusiness. These databases allow a business toenter, gather, and retrieve specific companyinformation. Operational databases can storedifferent types of information such as trainingstatus, personal employee information, andprevious proposal information. Storinginformation in a centralized area can increaseretrieval time for users. Operational databasesare important when information is neededquickly.
Distributed Database• Distributed database is a database in which storage devices are not all attached to a common processing unit such as the C.P.U. It may be stored in multiple computers located in the same physical location, or may be dispersed over a network of interconnected computers. Collections of data can be distributed across multiple physical locations. A distributed database can reside on network servers on the Internet, on corporate intranets or extranets, or on other company networks. The replication and distribution of databases improves database performance at end- user worksites. To ensure that the distributive databases are up to date and current, there are two processes: replication and duplication The replication process can be very complex and time consuming depending on the size and number of the distributive databases. This process can also require a lot of time and computer resources. Duplication on the other hand is not as complicated.
Relational DBMS• Relational DBMS or RDBMS if the database relationships are treated in the form of a table. there are three keys on relational DBMS 1)relation 2)domain 3)attributes. A network means it contains fundamentel constructs sets or records.sets contains one to many relationship,records contains fields statical table that is composed of rows and columns is used to organize the database and its structure and is actually a two dimension array in the computer memory. A number of RDBMSs are available, some popular examples are Oracle, Sybase, Ingress, Informix, Microsoft SQL Server, and Microsoft Access.
Hierarchical DBMS• A DBMS is said to be Hierarchical if the relationships among data in the database are established in such a way that one data item is present as the subordinate of another one. Here subordinate means that items have parent-child relationships among them. Direct relationships exist between any two records that are stored consecutively. The data structure "tree" is followed by the DBMS to structure the database. No backward movement is possible/allowed in the hierarchical database. Hierarchical data model was developed by IBM in 1968 and introduced in I.M.S. (Information Management System).This model is like a structure of a tree with the records forming the nodes and fields forming the branches of the tree. In the hierarchical model,records are linked in the form of an organization chart. A tree structure may establish on-to-many relationship.
Network DBMS• Network DBMS if the relationships among data in the database are of type many-to-many. The relationships among many-to-many appears in the form of a network. Thus the structure of a network database is extremely complicated because of these many-to-many relationships in which one record can be used as a key of the entire database. A network database is structured in the form of a graph that is also a data structure. Though the structure of such a DBMS is highly complicated however it has two basic elements i.e. records and sets to designate many-to-many relationships. Mainly high-level languages such as Pascal, COBOL andFORTRAN etc. were used to implement the records and set structures.
Object-Oriented Database• An Object Database (also object-oriented database management system) is a database management system in which information is represented in the form of objects as used in object-oriented programming. Object databases are different from relational databases and belongs together to the broader database management system. Object databases have been considered since the early 1980s and 1990s. Object databases main usage is in object oriented areas.
Trends in Database ManagementMulti dimensional Data AnalysisData WarehouseData miningHypermedia in Database on the Web