Connecting with Computer Science Chapter Review: A database is a collection of logically related information used in an application to create meaningful output for end users Normalization is the process of structuring tables to eliminate un-wanted redundancies and dependencies Database information is kept in a sequential order, but you can view the order of records in different formats by creating indexes and assigning sort keys Primary keys are used to uniquely identify table entries; foreign keys are columns in one table that reference a primary key in another table The manner in which one table relates to another table is called a relationship The types of relationships discussed are: one-to-one (1:1), one-to-many (1:M) and many-to-many (M:M) First Normal Form [1NF] eliminates repeated fields Second Normal Form [2NF] dictates that every column that is not part of the primary key is fully dependant on the primary key Third Normal Form states that no column can depend on any other column than the primary key Fourth and Fifth Normal Form are rarely used but further break down tables into non-dependant, nonredundant forms The steps for designing a database are: Investigate, Create a master column list, create the tables, assess the relationships, analyze the design and re-evaluate Structured Query Language (SQL) is a powerful database language for: Defining, Maintaining, Querying and administering data Key Terms: Cardinality: Column (field or attribute): Composite key: Database: Shows the numeric occurrences between entities in an ER model (228) A specific piece of information in a table row (211) A primary key made up of more than one column (220) Data that has been logically related and organized into a file or set of files to allow access and use (207) DBMS: A program for managing storage, access and modifications to a database (209) Determinant: In a database, any column you can use to determine the value assigned to another column in the same row (220) Domain: Set of possible values for a column (212) Entity relationship model: A data model that represents how all tables interact and relate to each other in the database (228) First Normal Form (1NF): Eliminating repeating fields or groups of fields from the table and confirming that every column has only value by creating a new record in the table (218) Foreign key (FK): A column in table that relates to a primary key in another table (226) Functional dependency: A column's value is dependent on another column's value (220) Index: A special file that occupies its own space and specifies one or more columns that determine how information stored in the table can be accessed more efficiently (213) Many-to-Many Relationship: Many instances of one entity or table are associated with many instances of another entity (228) Normalization: A database design process that structures tables to eliminate duplication and inconsistencies in the data structure (216) One-to-Many Relationship: One instance of an entity is associated with zero to many instances of another table (227) One-to-One Relationship: One instance of an entity is associated with only one instance of another entity (228) Primary Key (PK): A column or combination of columns that uniquely identifies a row in a table (219) Relationship: How one entity or table works with another (226) row (record or tuple): A collection of columns (211) Second Normal Form (2NF): First Normal Form has already been applied to the table, and every column that is not part of the primary key is fully dependant on the primary key (220) Sort Key: In a database table or more columns used to determine the data's sort order normalization: a database design process that structures tables to eliminate duplication and inconsistencies in the data structure (214) SQL: A special language used to maintain database structure and modify, query and extract information (209) Table (or entity): Data arranged in rows and columns, much like a spreadsheet (211) Third Normal Form (3NF): Eliminates columns that are not dependent on only the primary key (222) transitive dependency: One column is dependent on another column that is not a primary key (222) Test Your-self: 1.) What is a database? Give an example of a database in current use that affects you data that has been logically related and organized into a file or set of files to allow access and use MySQL 2.) The table is listed in what order (primary key)? Ascending order 3.) Write a SQL SELECT statement to list the table's contents in order of wins SELECT * FROM baseball ORDER BY wins; 4.) Write a SQL SELECT statement to list the table's contents in order of wins and team SELECT * FROM baseball ORDER BY wins AND team; 5.) Write a SQL INSERT INTO statement to add the team Bears The bears have wins and losses INSERT INTO baseball(team, wins, losses) VALUES (‘Bears’, ‘3’, ‘9’); 6.) Write a SQL INSERT INTO statement to add the team Lions The Lions have wins and losses INSERT INTO baseball (team, wins, losses) VALUES (‘Lions’, ‘9’, ‘3’); 7.) Write a SQL SELECT statement to list all the table's contents SELECT * FROM baseball; 8.) What is normalization and what problems does it solve a database design process that structures tables to eliminate duplication and inconsistencies in the data structure 9.) Explain the first normalization forms 1ST NF: eliminating repeating fields or groups of fields from the table and confirming that every column has only value by creating a new record in the table 2ND NF: first normal form has already been applied to the table, and every column that is not part of the primary key is fully dependant on the primary key 3RD NF: eliminates columns that are not dependent on only the primary key 10.) List and explain the six steps for designing a database Step 1: Investigate and define Research and investigate the information you want plan to model Define the purpose of the database and how you plan to use it Use end-use documents to define fields Involve endusers Step 2: Make a master column list Create the input fields Review documents Step 3: Create the tables After all the tables and columns have been defined It is time to group them into tables Try to follow the rules of normalization Look for duplicates tables or data types and try to eliminate them Step 4: Work on relationships Finalize the relationship you have observed during the design and normalization process In database design, a relationship defines how one table works with another Relationships can either be: 0:1, 0:M, 1:1, 1:M, M:1, M:M Step 5: Analyze the design Review your design and search for design errors refining tables as needed Ultimately aim for 3rd NF Create a database model, to serve as a visual representation This model is called an ER model Step 6: Re-Evaluate Reevaluate database performance and ensure that it meets all your reporting and form needs Include end-users and explain each table and field being used Make sure fields have been defined to address end users' requirements 11.) Create a normalized database to support a space shuttle launching application The government wants to keep track of: astronauts, space shuttles and launch history Define the tables, primary and foreign keys and indexes Make sure the tables are finalized in the 3rd normalized state 12.) Draw an ER model to represent the space shuttle launching application designed in question 11 Make sure you show the relationships, label the cardinality, and show primary and foreign keys Astronaut Data Space Shuttle data Field Name Error_Log_Date Error_Log_Time User_Code User_First User_Last Error_Code Error_ Code_Desc User_Password Error_Log_Desc Error_Status_Code Error_Priority_Code Field Size 15 25 40 10 80 if text Space Shuttle data Field Type Date Time Text Text Text Text Text Text Text Yes / No or Text Number Sample Data 12/15/2010 2:24:32 PM KATIE KAYTLEN ANDERSON LOG INCORRECT LOGIN MONK USER INPUT WAS BAD C Completed U Unresolved I In process of being fixed Can contain a number from 5: - Very High - High - Medium - Low - Very Low 13.) 14.) ... to define fields Involve endusers Step 2: Make a master column list Create the input fields Review documents Step 3: Create the tables After all the tables and columns have been defined... another Relationships can either be: 0:1, 0:M, 1:1, 1:M, M:1, M:M Step 5: Analyze the design Review your design and search for design errors refining tables as needed Ultimately aim for 3rd