Introduction to Database Systems Computer Science & Engineering Introduction to Database Systems This lecture will cover the use of some basic functions provided by EXCEL. We will be explore how these functions work and how they can be used to solve problems.

Database Terms Data Information A collection of numbers and text 273459368 Information Meaning derived from the data SSN: 273-45-9368

What is a database? Examples of computer databases A large collection of data stored in a well-defined structure You can think of a database as An electronic filing system A repository for large amounts of information Example of a paper database Telephone book Examples of computer databases Ohio State stores student information in a database Insurance companies store policy holder information in a database Your employer stores your information in a database

Database Software How do I create a database? Purchase the software We will use MS Access 2010, but there are many database software products Oracle Sybase SQL Server How do I access information in the database? Purchase a Database Management System (DBMS) A DBMS is a collection of programs that enable you to enter, organize, and select data in a database. We will use MS Access 2013, but there are many database management software products

Steps when setting up a Database The design should be initially created schematically, and then the database should be created using the chosen database software

1. Decide what information you will store in the database Research Papers database First Name Charge Amount Last Name Charge Date Address Payment Amount City Payment Type State Payment Date Zip Code   Home Phone This database is a very simplistic one. Most databases you create will be much more complex.

2. Create the layout of the database What tables do you need in your database? What is a table? An entity used to organize information by categories of like information

Research Papers Database Tables Client Stores client information Charges Stores client charges information Payments Stores client payment information PaymentMethod Stores the payment method Credit Card Cash Check

2. Create the layout of the database What fields do you need in your database? What is a field? An attribute (piece of information) of the table/entity. How will you set them up? Divide Tables into Inseparable Fields Address as 1 field – 17 Main St. New York, New York 10002 Address as 4 fields Street Address - 17 Main St. City - New York State - New York Zip code – 10002

Research Papers Database Table Name: Client Fields: Client ID   First Name Last Name Address City State Zip Code Home Phone Charges Charge Amount Charge Date Payments Payment Amount Payment Type Payment Date PaymentMethod MethodID MethodType

2. Create the layout of the database Fields contain field types/data types and field properties What is a field Type/Data Type? Defines the type of information that can be stored. i.e. text, numbers, dates, etc. What is a field Property? Field size Input Mask Validity Default Value

Research Papers Database Table Name: Client Field Type/ Data Type Properties   Fields: Client ID Text 5 Characters long Primary Key First Name 25 Characters long Last Name 50 Characters long Address 60 Characters long City State 2 Characters long Default Value Zip Code Home Phone 10 Characters long Input Mask Charges Field Type Charge Amount Currency None Charge Date Date Input Mast Payments Payment Amount Payment Type Payment Date PaymentMethod MethodID MethodType 20 Characters long

2. Create the layout of the database What will be the primary key for each table? A field, or a collection of fields, whose values uniquely identify each record in a table

Research Papers Database Table Name: Client Field Type/ Data Type Properties   Fields: Client ID Text 5 Characters long Primary Key First Name 25 Characters long Last Name 50 Characters long Address 60 Characters long City State 2 Characters long Default Value Zip Code Home Phone 10 Characters long Input Mask Charges Field Type Charge Amount Currency None Charge Date Date Input Mast Payments Payment Amount Payment Type Payment Date PaymentMethod MethodID MethodType 20 Characters long

CSE 2111 Introduction to Database Systems File Primary Key Table Data Type/Field Type Each Record is made up of 8 Fields A field, or combination of fields, which uniquely identifies a record in a database Primary Key Field Properties CSE 2111 Introduction to Database Systems

How is a database Organized? (Hierarchy of Data in a database) Table File 16 Records Each Record is made up of 8 Fields CSE 2111 Introduction to Database Systems

Tables & Relationships Quick Review-Steps when Creating a Database Steps to complete before creating the database using the software Decide what information you will store in the database Create the layout of the database Create a relationship diagram to identify the table relationships, primary keys and foreign keys 4. Create the database using the database software

Create the database using the database software Create the Database File Create the tables Fields Primary keys Field Types Field Properties We know the information we want to store, but how do we match a customer’s name to their charges and payments? We need a way to relate these two tables to extract useful information. We can relate these two tables by matching the Client ID We do this by “Joining” the tables Create the Relationships

∞ 1 Parent Child Table Name: Client Primary Key: ClientID Table Name: Payments Primary Key: None FK: ClientID On Payments table

Relationship Rules Must be a primary key in least one of the tables in the relationship. The related fields must be the same data type number, text etc. The foreign key field must contain the same information as the primary key field. The field names on each table do not have to match as long as the information is the same. FK: ClientID On Payments table Table Name: Client Primary Key: ClientID Table Name: Payments Primary Key: None

Referential Data Integrity A set of rules that specifies what records may exist in each table A record input with a foreign key must always have a matching record in the primary key table in the relationship

Cascade Delete Related Records Removing any entry in a primary key field will automatically remove all entries in foreign key fields of related tables. Cascade Update Related Records Updating any entry in a primary key field will automatically update all entries in foreign key fields of related tables.

∞ ∞ ∞ 1 1 1 Parent Parent Child Child Child Parent Table Name: Client FK: ClientID On Payments table FK: ClientID On Charges table Table Name: Client Primary Key: ClientID Parent Parent 1 1 Child ∞ Child ∞ Table Name: Payments Primary Key: None Table Name: Charges Primary Key: None ∞ Child FK: PaymentType On Payments table 1 Parent Table Name: MethodTypes Primary Key: MethodID A Foreign Key (FK) is a field that defines the relationship between 2 tables.

Access DBMS “objects”: Tables - a list of data organized into fields and records Queries - question structures to sort, filter and select specific information Forms - structures for screen views of data Reports - structures for written output of data Program Modules & Macros - program code to perform specific actions CSE 2111 Introduction to Database Management Systems

CSE 2111 Introduction to Database Management Systems Tables A table is an entity used to organize information by categories of like information A database is made up of one or more tables CSE 2111 Introduction to Database Management Systems

CSE 2111 Introduction to Database Management Systems Queries Used to extract information from a database CSE 2111 Introduction to Database Management Systems

CSE 2111 Introduction to Database Management Systems What is a database Form? Structures for screen view and input of information Used to simplify viewing and inputting of information Datasheet View Form View CSE 2111 Introduction to Database Management Systems

What is a database Report? Structures for viewing written output of information CSE 2111 Introduction to Database Management Systems