CIS 103 — Applied Computer Technology Last Edited: September 17, 2010 by C.Herbert 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. 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. CIS 103 Applied Computer TechnologyDBMS part 1, slide 2

Using Database Management Systems A database is 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 system is 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. CIS 103 Applied Computer TechnologyDBMS part 1, slide 3

Using Database Management Systems 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 an instance of the entity. Student is the entity. John Smith is an instance of the entity. CIS 103 Applied Computer TechnologyDBMS part 1, slide 4 Student snumlastfirststreetcitystatezipphonemajorgpa S00188SmithJohn111 Oak Ave.PrincetonNJ CIS3.43 S03154JonesMary212 Maple St.HanoverNH Computer Science 3.62 S10843JarvisFred123 Spruce St.ProvidenceRI English3.07

Using Database Management Systems 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. CIS 103 Applied Computer TechnologyDBMS part 1, slide 5

Using Database Management Systems Many modern databases are enterprise-wide databases. An enterprise-wide database is a single database with all of the data for an enterprise, such as a business, a government agency, or some other kind of organization. CIS 103 Applied Computer TechnologyDBMS part 1, slide 6

Student snumlastfirststreetcitystatezipphonemajorgpa S00188SmithJohn111 Oak Ave.PrincetonNJ CIS3.43 S03154JonesMary212 Maple St.HanoverNH Computer Science 3.62 S10843JarvisFred123 Spruce St.ProvidenceRI English3.07 S36912WilliamsCathy231 Ash TerraceNew HavenCT Biology2.64 Student snumlastfirststreetcitystatezipphonemajorgpa S00188SmithJohn111 Oak Ave.PrincetonNJ CIS3.43 S03154JonesMary212 Maple St.HanoverNH Computer Science 3.62 S10843JarvisFred123 Spruce St.ProvidenceRI English3.07 S36912WilliamsCathy231 Ash TerraceNew HavenCT Biology2.64 Using Database Management Systems 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. CIS 103 Applied Computer TechnologyDBMS part 1, slide 7

Student snumlastfirststreetcitystatezipphonemajorgpa S00188SmithJohn111 Oak Ave.PrincetonNJ CIS3.43 S03154JonesMary212 Maple St.HanoverNH Computer Science 3.62 S10843JarvisFred123 Spruce St.ProvidenceRI English3.07 S36912WilliamsCathy231 Ash TerraceNew HavenCT Biology2.64 Student snumlastfirststreetcitystatezipphonemajorgpa S00188SmithJohn111 Oak Ave.PrincetonNJ CIS3.43 S03154JonesMary212 Maple St.HanoverNH Computer Science 3.62 S10843JarvisFred123 Spruce St.ProvidenceRI English3.07 S36912WilliamsCathy231 Ash TerraceNew HavenCT Biology2.64 Our student table has a column for last name, a column for first name, and so on. Using Database Management Systems An attribute is something that describes an entity. There is a column in a database table for each attribute of an entity. CIS 103 Applied Computer TechnologyDBMS part 1, slide 8

Student snumlastfirststreetcitystatezipphonemajorgpa S00188SmithJohn111 Oak Ave.PrincetonNJ CIS3.43 S03154Jones Mary 212 Maple St.HanoverNH Computer Science 3.62 S10843JarvisFred123 Spruce St.ProvidenceRI English3.07 S36912WilliamsCathy231 Ash TerraceNew HavenCT Biology2.64 Using Database Management Systems 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. CIS 103 Applied Computer TechnologyDBMS part 1, slide 9

Student snumlastfirststreetcitystatezipphonemajorgpa S00188SmithJohn111 Oak Ave.PrincetonNJ CIS3.43 S03154JonesMary212 Maple St.HanoverNH Computer Science 3.62 S10843JarvisFred123 Spruce St.ProvidenceRI English3.07 S36912WilliamsCathy231 Ash TerraceNew HavenCT Biology2.64 Student snumlastfirststreetcitystatezipphonemajorgpa S00188SmithJohn111 Oak Ave.PrincetonNJ CIS3.43 S03154JonesMary212 Maple St.HanoverNH Computer Science 3.62 S10843JarvisFred123 Spruce St.ProvidenceRI English3.07 S36912WilliamsCathy231 Ash TerraceNew HavenCT Biology2.64 In our example, student number is the primary key for the student table. Using Database Management Systems A primary key is an attribute that has a different value for each instance of an entity, so we can identify that instance. CIS 103 Applied Computer TechnologyDBMS part 1, slide 10 Each student has a different student number.

Using Database Management Systems 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. CIS 103 Applied Computer TechnologyDBMS part 1, slide 11 Classroom

Using Database Management Systems Information about how a database is organized – in other words, data about the data – is called metadata. We will see more about metadata later. CIS 103 Applied Computer TechnologyDBMS part 1, slide 12 Classroom

Relational Database Software 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. CIS 103 Applied Computer TechnologyDBMS part 1, slide 13

Relational Database Software 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). CIS 103 Applied Computer TechnologyDBMS part 1, slide 14

Relational Database Software 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. CIS 103 Applied Computer TechnologyDBMS part 1, slide 15

Relational Database Software 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. — § — CIS 103 Applied Computer TechnologyDBMS part 1, slide 16