Chapter 4c, Database H Definition H Structure H Parts H Types

Chapter 4c, Database n database - organized collection of data that may reside in multiple files n database software - stores, organizes and retrieves the data

Chapter 4c, The Electronic File Cabinet: Database Basics Like word processors, spreadsheets, and graphics programs, database programs are applications. Database programs are designed to maintain collections of information stored on computer disks. 8.04

Chapter 4c, The Electronic File Cabinet: Database Basics –What Good Is a Database? –What’s a Good Database System? –Database Anatomy –Database Operations 8.04

Chapter 4c, What Good Is a Database? Databases make it easier to: –store large quantities of information. –retrieve information quickly and flexibly. –organize and reorganize information. –print and distribute information in a variety of ways. 8.05

Chapter 4c, What’s a Good Database System? (Properties) n data integrity- the validity of the data n data independence - the way an application program displays the data does not have to be the same way the data is physically stored

Chapter 4c, What’s a Good Database System? (Properties) n data redundancy - repetition of data n data security - access to data (sensitive) or protection against loss n data maintenance - ease of adding, deleting and updating records

Chapter 4c, Database Anatomy: An Electronic File Cabinet 8.06 Databases are … Bell, Pat 123 Eagle Cr. Anytown, OR 123 Eagle Cr. made up of files, which are… made up of records, which are… made up of fields.

Chapter 4c, Database Terms

Chapter 4c, Database Terms One unit or piece of data; the more precise each field is, the more efficient the database management is when you start searching and manipulating data Examples: First name middle initial phone no. catalog no.

Chapter 4c, Database Terms A collection of all related fields about one person, place or thing Examples: a driver’s license, all the info about each catalog item

Chapter 4c, Database Terms A collection of records related to the same topic Examples: All drivers licenses for a state, all items in a catalog

Chapter 4c, Database Terms A field containing different (unique) information for each record in a database; if you don’t identify a key field, Access can assign one. Examples: SS number catalog item # filename customer # numeric count

Chapter 4c, Database Terms Items attached to a database to hold data stored in the database Examples: Tables forms reports queries macros modules

Chapter 4c, Database Terms An association established between tables using fields that the tables have in common Examples: Using Social Security #, item number, or Vendor no. to tie data from one table to data from another table

Chapter 4c, View View: a display of the information in fields based on a particular arrangement of field data. Two views: list (in Access this is called Datasheet view) and browse (form view) list - a table, see records line by line browse - see one record at a time in the guise of an onscreen form 8.07

Chapter 4c, Database Operations Database commands are used to retrieve, organize, print and distribute database information. –Import: –Browse: –Sort: –Report: –Query(Filter):

Chapter 4c, Import:receive data in the form of text files

Chapter 4c, Browse navigate through information by just looking at it.

Chapter 4c, Sort: rearrange records (alphabetically or numerically).

Chapter 4c, Report: printout of an ordered list of records.

Chapter 4c, Queries/Filters: search or select one or more specific records A set of criteria applied to records in order to show a subset of the records or sort the records

Chapter 4c, The User’s View 8.09 Database programs can produce a variety of reports (or printouts). Customized reports display an ordered list of selected records and fields

Chapter 4c, Database Objects

Chapter 4c, Database Objects The primary unit of a database that stores field names, field descriptions, field controls, and field data. Tables display multiple records in column/row format similar to a spreadsheet layout.

Chapter 4c, Database Objects A structured guideline used to search database tables and retrieve records that meet specific conditions.

Chapter 4c, Database Objects An aesthetically pleasing layout of table data designed to display one record on-screen at a time.

Chapter 4c, Database Objects An organized format of database data design to generate printouts that provide meaningful information

Chapter 4c, Database Objects A mini program that stores a set of instructions designed to perform a particular task.

Chapter 4c, Database Objects A collection of Visual Basic programming procedures stored together to customize the Access environment.

Chapter 4c, Database Objects n When you create a new database, you have to name the database and identify the folder to store. n Eventually you will create objects within the database, and Access will store the objects together in the same database file.

Chapter 4c, Special-Purpose Database Programs Geographical information systems (GISs): (GISs): include geographic and demographic data in map form, databases: electronic phone directories Ready-to-use, encyclopedias, atlases, and similar reference materials. 8.10

Chapter 4c, Special-Purpose Database Programs Personal information managers (PIMs): an electronic organizer that is customized to fit individual needs. 8.10

Chapter 4c, Rules of Thumb: Dealing with Databases n Choose the right tool for the job. n Plan ahead. n Start small and test your database design. n Make data consistent. n Make use of automatic data checking. n Query with care. n Develop smart search methods. 8.12

Chapter 4c, Structure of the data n lowest n lowest level - characters n characters n characters are combined to form a field (single item of information) n collection n collection of fields is a record n records n records are stored in file(s) n it n it is up to the database designer how the data is to be organized, it is up to the database software to retrieve, and store the information

Chapter 4c, Types of Database Software n file management programs n database management systems

Chapter 4c, File Management Programs n a computer program that allows the user to store and manage information on a single file n used by individuals and small businesses n easy to learn, low price, less complex n example - Works database

Chapter 4c, Database Management Systems n A program that stores data in files structured into fields and records. Can use data stored in one file to match with several other files n more expensive, more complex n four different structures

Chapter 4c, Database Structures to Link Files n Hierarchical n Network n Relational n Object-Oriented

Chapter 4c, Hierarchical Databases n links data with a hierarchical relationship n group fields together to form a special relationship- looks like a pyramid n limits the way you can search for information based on the relationships

Chapter 4c, Hierarchical Design

Chapter 4c, Network Databases n also based on relationships, but a child can have more that one parent or none

Chapter 4c, Network Design

Chapter 4c, Relational Databases n Most popular - Access n Information related through a common field called a key n key field - is a field that occurs in two or more files and serves as a bridge between them

Chapter 4c, Relational Database

Chapter 4c, Object-Oriented Databases n based on the relationships of the objects within the database n newest type - heavily used in multimedia objects

Chapter 4c, Parts of the DBMS Software n Data Definition Language- used to describe the structure (schema) n Schema outlines the data - each field must be identified with a name, length and type n Data Manipulation Language - use to view, add, delete, sort and modify records

Chapter 4c, Parts Continued n Query Language-asks questions of the dB n Report Generator - design and generate reports based on the information within the dB

Chapter1, Unit C Slide No. 49 Questions