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Using Database Management Systems

Using Database Management Systems. Using Database Management Systems. A student who successfully completes this chapter should be able to: define the database terms used in the chapter. describe what relational database management systems are.

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Using Database Management Systems

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  1. UsingDatabase Management Systems

  2. Using Database Management Systems CIS 103 Applied Computer Technology A student who successfully completes this chapter should be able to: • define the database terms used in the chapter. • describe what relational database management systems are. • construct SQL queries to extract specified data from a database table. • create database queries for a Microsoft Access database. • export the results of Microsoft Access queries into Microsoft Excel for formatting, presentation, and analysis.

  3. Using Database Management Systems CIS 103 Applied Computer Technology A databaseis an organized collection of data, usually one that that can be stored and processed using a computer system. It can be thought of as an electronic filing system. A database management systemis a collection of software that enables users to store, organize, analyze, and extract information using a database. A relational database is a database with data organized as a set of tables. Almost all modern databases are relational databases.

  4. Using Database Management Systems CIS 103 Applied Computer Technology The things we wish to keep track of in a database are called entities. In a relational database, there is a table for each entity. The word entity refers to the general object that each table describes. Each specific object is called aninstanceof the entity. Student is the entity. John Smith is an instance of the entity.

  5. Using Database Management Systems CIS 103 Applied Computer Technology Modern databases have many tables, not just one. A university records and registration system might have tables for students, courses, sections of courses, teachers, classrooms, student registration records, teaching assignments, and so on.

  6. Using Database Management Systems CIS 103 Applied Computer Technology Many modern databases are enterprise-wide databases. An enterprise-wide databaseis a single database with all of the data for an enterprise, such as a business, a government agency, or some other kind of organization.

  7. Using Database Management Systems CIS 103 Applied Computer Technology There is a row in a database table for each instance of the entity. In our student table, there is a row for each student.

  8. Using Database Management Systems Our student table has a column for last name, a column for first name, and so on. CIS 103 Applied Computer Technology An attributeis something that describes an entity. There is a column in a database tablefor each attribute of an entity.

  9. Using Database Management Systems CIS 103 Applied Computer Technology The intersection of a row and a column in a database table is called a field. Each field holds the value of one attribute for one instance of the entity.

  10. Using Database Management Systems In our example, studentnumber is the primary key for the student table. Each student has a different student number. CIS 103 Applied Computer Technology A primary key is an attribute that has a different value for each instance of an entity, so we can identify that instance.

  11. Using Database Management Systems CIS 103 Applied Computer Technology The full database name for a column includes the table name and the column name, separated by a comma. student.snum , student.last , student.gpa , etc.

  12. Using Database Management Systems CIS 103 Applied Computer Technology Information about how a database is organized – in other words, data about the data – is called metadata. We will see more about metadata later.

  13. Relational Database Software CIS 103 Applied Computer Technology Structured Query Language – SQL – is a language used to query a relational database. SQL is both a data definition language (DDL) used is to define the structure of a database and a data manipulation language, (DML) used to manipulate data in a database, including extracting data from a database. Technically, any SQL statement is a query, but people generally use the word query to specifically mean statements that extract data from a database.

  14. Relational Database Software CIS 103 Applied Computer Technology Structured Query Language – SQL – is a language used to query a relational database. A standard definition of the SQL language is maintained by the American National Standards Institute (ANSI) and the International Organization for Standardization (ISO).

  15. Relational Database Software CIS 103 Applied Computer Technology Most of the major relational database management systems in use today, such as The Oracle Database, MySQL, Microsoft SQL Server, Ingres, and Microsoft Access, use SQL.

  16. Relational Database Software CIS 103 Applied Computer Technology In the following sections we will learn about SQL queries to extract data from a database, how to use them in Access, and how to use the Access Query Wizard and Design View to extract data without using SQL. — § —

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