SQL

2. Q2: Observe the E/R diagram below. The database already contains the relation "pub- lication". You need to write the appropriate table creation command for the subclass "article". Make sure that you include any appropriate constraints. Use the field names represented in the diagram. All fields should be of type varchar(10). Submit your statement in file 02.sql. title year publication isa journal volume article number 3. Q3: Select which statement is accurate with respect to the E/R diagram below. course teaches professor 1. Each professor teaches at most one course 2. Each professor teaches exactly one course 3. Each professor teaches at least one course 4. Each course is taught by at most one professor 5. Each course is taught by exactly one professor 6. Each course is taught by at least one professor Format your answer in a query as follows: SELECT answer where answer is a number (1 through 6), e.g., SELECT 1, if your answer to the question is choice number w from the the list above. Submit your answer as a query in file 03. aql. 4. Q4: Write the SQL DDL commands (CREATE TABLE statements) to convert the ER diagram below to a database schema. All attributes should be integers (type int). Use the attribute names as depicted in the diagram, and declare all the appropriate constraints. Do not create a separate table for relationship R. When you define combined keys, please list the attributes in the combined keys in alphabetical order in the key definition. Enter all the CREATE TABLE statements, in the proper order, in file 04.sql. R B isa h s D