Fox MIS Spring 2011 Database Week 6 Mid-term Review

Format of Mid-term Exam TIME: 11:00 am -12:00 LOCATION: SP114 FORMAT: –Multiple Choices (10-15 questions) –Q&A (4-6 questions) –ERD (1 question) Content ratio (approximately): BI 10-15%, ERD 30-35%, SQL 50-60%

Business Intelligence What is Business Intelligence (BI)? What’s the main role of BI in business List some technologies supporting BI. List BI skill and knowledge clusters. What is BI maturity? What are the four stages of the BI maturity model? Explain why BI is an architecture and a collection of i ntegrated operational as well as decision-support ap plications and databases that provide the business c ommunity easy access to business data.

Mental Map of BI

Database Design Database Models, advantages & disadvantages The uniqueness of relational model The role of DBMS, DBMS functions

ERD Entities Attribute Primary key, foreign key Relationships (1:M, M:1, M:N) Referential integrity

Drawing ERD Steps: –Identify entities –Insert primary keys –Insert attributes (independence) –Identify relationships –Add bridge entity to simplify M:N relationships –Add foreign keys and build relationships Tips: for transactional database, it’s common to connect all “physical” entities to the core trans actional entity/table.

Frequent Made Mistakes Add wrong attributes Add record as attributes (e.g. laptop or product n ame) Forgot to identity relationships Couldn’t identify M:N relationships Wrong relationships (e.g. customer store) Forgot referential integrity Loops

First Invoice

Second Invoice /10/2008 Jason Mraz 72 Spring Street New York, NY Jason Mraz 72 Spring Street New York, NY The Big Short Economics Databases R Amazing IS TOTAL Tax Grand Total The Big Short Economics Databases R Amazing IS TOTAL Tax Grand Total

Third Invoice /4/2008 6/12/2008 Sunny California 610 W. Ash St San Diego, CA Sunny California 610 W. Ash St San Diego, CA To the End of the Land Novel Databases R Amazing IS TOTAL Tax Grand Total To the End of the Land Novel Databases R Amazing IS TOTAL Tax Grand Total

SQL Database Manipulation Language (DML) SHOW TABLES, DESCRIBE SELECT, *, WHERE, ORDER BY AND & OR COUNT, DISTINCT DELETE, INSERT, UPDATE JOIN, ALIAS Database Definition Language (DDL) CREATE TABLE/DATABASE DROP TABLE/DATABASE ALTER, PRIMARY KEY, FOREIGN KEY

SELECT, COUNT, DISTINCT, WHERE Table: customer_list, Databse: Sakila –Where does Judy Gray live? SELECT * FROM CUSTOMER_LIST WHERE NAME= 'JUDY GRAY‘ (or NAME LIKE ‘JUDY GRAY’) –How many countries do our customers live in? SELECT COUNT(DISTINCT COUNTRY) FROM CUSTOMER_LIST –How many customers live in Egypt? SELECT COUNT(ID) FROM CUSTOMER_LIST WHERE COUNTRY = 'EGYPT' –What cities in Egypt do our customers live in? SELECT DISTINCT CITY FROM CUSTOMER_LIST WHERE COUNTRY = 'EGYPT' –How many customers live outside of the United States? SELECT COUNT(ID) FROM CUSTOMER_LIST WHERE COUNTRY <> 'UNITED STATES'

LIKE, AND, ORDER BY Table: film –How many films are less than or equal to 90 minutes in their lengths? SELECT COUNT(FILM_ID) FROM FILM WHERE LENGTH <= 90 –How many films are about astronauts? SELECT COUNT(FILM_ID) FROM FILM WHERE DESCRIPTION LIKE '%ASTRONAUT%' –List of the movie titles which are about astronauts and their length are less than 90 minutes SELECT TITLE FROM FILM WHERE (DESCRIPTION LIKE '%ASTRONAUT%') AND (LENGTH < 90) –List of the movie titles and their length in descending order according to the length SELECT TITLE, LENGTH FROM FILM ORDER BY LENGTH DESC

INSERT, UPDATE, DELETE Table: retail_sales_feb Put yourself as the customer –You bought it from Sales_rep whose name is Smith at Feb –Your order_no is and cust_no is 3456 DESCRIBE RETAIL_SALES_TAB (you might need this statement to see data type for each field) INSERT INTO RETAIL_SALES_FEB VALUES (' ', 34567, 3456, ‘Yang Yang', ‘Smith', 'CB03', 'Bike', 'Sport', 1, '$250', '$250') Put person next to you as the customer –You don’t know anything about that person except the name and intend to fill the rest of the fields later on –Note: you need to figure out what the key is and make it up DESCRIBE RETAIL_SALES_TAB (Primary key should be “NO” in Null field) INSERT INTO RETAIL_SALES_FEB (ORDER_NO, CUSTOMER) VALUES (45678, 'Joe Smith') You found out that the person you bought from was not Min but Smith. Correct the information UPDATE RETAIL_SALES_FEB SET SALES_REP = 'Smith' WHERE ORDER_NO = You want to cancel your order and make it as if it never happened DELETE FROM RETAIL_SAELS_FEB WHERE ORDER_NO = 34567

Join Output customer names, payment amount, CSR name, a nd rental date from database sakila: SELECT rental.rental_date, customer.first_name, customer.last_na me, payment.amount, staff_list.name FROM rental, customer, payment, staff_list WHERE rental.rental_id=payment.rental_id AND rental.customer_id=customer.customer_id AND rental.staff_id=staff_list.ID You can also use table1 INNER JOIN table2 ON conditions In above query, how many tables are joined? Why and w hen are these tables joined? How are these table joined?

Alias Just give another name for the output values –SELECT amount FROM payment AS p –SELECT amount, amount+1 FROM payment –SELECT amount AS "original_amount", amount+1 AS "new_am ount" FROM payment

CREATE DB and TABLE Create a database: CREATE DATABASE database_name Example: CREATE DATABASE my_db Create a table in a database: CREATE TABLE table_name ( column_name1 data_type, column_name2 data_type, column_name3 data_type,.... ) Example: CREATE TABLE Persons ( P_Id int, LastName varchar(255), FirstName varchar(255), Address varchar(255), City varchar(255) )

SQL Constraints Constraints are used to limit the type of data that can go into a table. Constraints can be specified when a table is created (with the CREATE TABLE statement) or after the table is created (with the ALTER TABLE statement). –NOT NULL –UNIQUE –PRIMARY KEY –FOREIGN KEY –CHECK –DEFAULT

CHECK The CHECK constraint specifies that the column "P_Id" must only include integers greater than 0. CREATE TABLE Persons ( P_Id int NOT NULL, LastName varchar(255) NOT NULL, FirstName varchar(255), Address varchar(255), City varchar(255), CHECK (P_Id>0) )

DEFAULT The DEFAULT constraint is used to insert a default value into a column. CREATE TABLE Persons ( P_Id int NOT NULL, LastName varchar(255) NOT NULL, FirstName varchar(255), Address varchar(255), City varchar(255) DEFAULT 'Sandnes' )

PRIMARY KEY The PRIMARY KEY constraint uniquely identifies each record in a database table. –Primary keys must contain unique values. –A primary key column cannot contain NULL values. –Each table can have only ONE primary key. CREATE TABLE Persons ( P_Id int NOT NULL, LastName varchar(255) NOT NULL, FirstName varchar(255), Address varchar(255), City varchar(255), PRIMARY KEY (P_Id) ) ALTER TABLE Persons ADD PRIMARY KEY (P_Id) –Creates primary key constraint for P_id column –Note: If you use the ALTER TABLE statement to add a primary key, the primary key column(s) must already have been declared to not contain NULL values (when the table was first created). ALTER TABLE Persons DROP PRIMARY KEY –Drops a PRIMARY KEY constraint

FOREIGN KEY A FOREIGN KEY in one table points to a PRIMARY KEY in another table. CREATE TABLE Orders ( O_Id int NOT NULL, OrderNo int NOT NULL, P_Id int, PRIMARY KEY (O_Id), FOREIGN KEY (P_Id) REFERENCES Persons(P_Id) ) ALTER TABLE Orders ADD FOREIGN KEY (P_Id) REFERENCES Persons(P_Id) –Create a FOREIGN KEY constraint on the "P_Id" column when the "Orders" table is already created ALTER TABLE Orders DROP FOREIGN KEY P_Id –Drops a FOREIGN KEY constraint

ALTER TABLE The ALTER TABLE statement is used to add, delete, or modify columns in an existing table. ALTER TABLE table_name ADD column_name datatype constraint(optional) ALTER TABLE table_name CHANGE OLD_COLUMN_NAME NEW_COLUMN_NAME datatype constraint(optional) –Old column name and new column name can be the same. ALTER TABLE table_name DROP COLUMN column_name ALTER TABLE Persons ADD DateOfBirth date ALTER TABLE Persons DROP COLUMN DateOfBirth ALTER TABLE Persons CHANGE DateOfBirth DateOfBirth year

MySQL Data Types (Text Types) Data typeDescription CHAR(size)Holds a fixed length string (can contain letters, numbers, and special characters). The fixed size is specified in parenthesis. Can store up to 255 characters VARCHAR(size)Holds a variable length string (can contain letters, numbers, and special characters). The maximum size is specified in parenthesis. Can store up to 255 characters. Note: If you put a greater value than 255 it will be converted to a TEXT type TINYTEXTHolds a string with a maximum length of 255 characters TEXTHolds a string with a maximum length of 65,535 characters BLOBFor BLOBs (Binary Large OBjects). Holds up to 65,535 bytes of data MEDIUMTEXTHolds a string with a maximum length of 16,777,215 characters MEDIUMBLOBFor BLOBs (Binary Large OBjects). Holds up to 16,777,215 bytes of data LONGTEXTHolds a string with a maximum length of 4,294,967,295 characters LONGBLOBFor BLOBs (Binary Large OBjects). Holds up to 4,294,967,295 bytes of data ENUM(x,y,z,et c.) Let you enter a list of possible values. You can list up to values in an ENUM list. If a value is inserted that is not in the list, a blank value will be inserted. Note: The values are sorted in the order you enter them. SETSimilar to ENUM except that SET may contain up to 64 list items and can store more than one choice

MySQL Data Types (Number Types) Data typeDescription TINYINT(size)-128 to 127 normal. 0 to 255 UNSIGNED*. The maximum number of digits may be specified in parenthesis SMALLINT(size) to normal. 0 to UNSIGNED*. The maximum number of digits may be specified in parenthesis MEDIUMINT(size) to normal. 0 to UNSIGNED*. The maximum number of digits may be specified in parenthesis INT(size) to normal. 0 to UNSIGNED*. The maximum number of digits may be specified in parenthesis BIGINT(size) to normal. 0 to UNSIGNED*. The maximum number of digits may be specified in parenthesis FLOAT(size,d)A small number with a floating decimal point. The maximum number of digits may be specified in the size parameter. The maximum number of digits to the right of the decimal point is specified in the d parameter DOUBLE(size,d)A large number with a floating decimal point. The maximum number of digits may be specified in the size parameter. The maximum number of digits to the right of the decimal point is specified in the d parameter DECIMAL(size,d)A DOUBLE stored as a string, allowing for a fixed decimal point. The maximum number of digits may be specified in the size parameter. The maximum number of digits to the right of the decimal point is specified in the d parameter

MySQL Data Types (Data Types) Data typeDescription DATE()A date. Format: YYYY-MM-DD Note: The supported range is from ' ' to ' ' DATETIME()*A date and time combination. Format: YYYY-MM-DD HH:MM:SS Note: The supported range is from ' :00:00' to ' :59:59' TIMESTAMP()*A timestamp. TIMESTAMP values are stored as the number of seconds since the Unix epoch (' :00:00' UTC). Format: YYYY-MM-DD HH:MM:SS Note: The supported range is from ' :00:01' UTC to ' :14:07' UTC TIME()A time. Format: HH:MM:SS Note: The supported range is from '-838:59:59' to '838:59:59' YEAR()A year in two-digit or four-digit format. Note: Values allowed in four-digit format: 1901 to Values allowed in two-digit format: 70 to 69, representing years from 1970 to 2069