All computer software is written in a specific programming language.
Programming languages have been divided into five separate generations based on how close they mimic human language.
- The first generation is binary.
- Binary is machine language made up of two symbols that signify off (0) and on (1)
- Assembler language is the second generation
- Assembler language uses English letters and symbols but relates them directly to binary.
- Third generation programming languages: FORTRAN, COBOL, Java, and Visual BASIC
- FORTRAN and COBOL are procedural languages that require the user to specify both the exact procedure to be carried out as well the data involved.
- Java is used for internet content and Visual BASIC is a visual programming language
- Fourth generation languages: allow users to choose procedures from a menu instead of having to specify them with code.
- Structured query language (SQL) is a fourth generation programming language
- uses syntax similar to human language to access, manipulate, and retrieve data from relational database management systems, which store data in tables
- Language elements of SQL include the following:
- Clauses: from, where, group by, having, and order by
- Expressions: produce scales and tables
- Predicates: three-valued logic (null, true, false) and Boolean truth values
- Queries: require a SELECT statement
- Statements: includes the semicolon (to terminate a statement)
- American National Standards Institute (ANSI) and the International Organization for Standardization have adopted SQL
- Structured query language (SQL) is a fourth generation programming language
- The fifth generation languages: is hoped that people will be able to speak directly to computers and have them carry out the verbal commands.
The five logical steps involved in computer programming:
- Problem definition
- Program desing
- Program preparation
- Program testing
- Program implementation