1- Explain how the following three tables are related.

2- Which table contains the foreign key(s), and

3- What is a foreign key?

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1- They are related because the primary keys from the "EMPLOYEE LIST" table and "PLANETS VISITED" table (which are EmployeeNumber, and PlanetNumber) are what link the three tables together, providing a relationship.

2- The "REASON FOR VISIT" table contains the two foreign keys.

3- More Importantly, EmployeeNumber and PlanetNumber are called foreign keys in the "REASON FOR VISIT" table, because they are what link the three tables together in a relationship.

1. An attribute that is a key of one or more relations, other than the one in which it appears.

2. Used to represent a relationship.

1. A [unique] key selected to be the key of relation.

2. The primary key is used as a foreign key for representing relationships.

Define the terms data and information.

Explain how the two terms differ.

Data is the recorded facts and numbers, and information is the knowledge derived from the data, presented in a meaningful context.

Information is also the process of the data when compared to other data.

Answer: Locking.

The problem that can occur when multiple people process a single database is known as “locking.”

What is a database?

What are integrated tables?

A database is a self-describing collection of integrated tables.

Integrated tables are tables that store both data and the relationships (i.e., foreign keys) among the data ("rows")

A database is self-describing because it contains a description of itself. 

SQL is a language for defining the structure and processing of a relational database.

It can be used as a stand-along language or it may be embedded in the application programs.

SQL is important because it serves as the query statement to the DBMS to do something. 

DBMS is a computer program that is used to create, process and administer the database.

The following are ALL of the functions of a DBMS program:

• Create the Database
• Create the Tables
• Create Supporting Structures (indexes)
• Read Database Data
• Modify Database Data (using SQL commands)
• Maintain Database Structures
• Enforce Rules (aka, referential integrity constraints)
• Control Concurrency
• Provide Security
• Perform Backup and Recovery

The reason a database is "self describing," is because it contains a description of itself.

It contains not only tables of user data, but also tables of data that describle that user data-- known as metadata, because it's "data about the data." It's important because metadata, "determines if particular tables, columns, indexes, or other substructures exist in a database." ~Book

A- Name 4 vendors of DBMS product.

B- Name the 5 DBMS products

Vendors:

1. Microsoft
2. Sun Microsystems
3. IBM
4. Oracle

Products:

• Microsoft Access (jet)
• Sun MySQL
• Microsoft SQL Server
• IBM DB2
• Oracle's Oracle Database

• Blocking / Locking
• Inconsistent Data (poly interpretables)
• Massive amounts of CPU power needed/Overloading