data bits many to many subkeys joinsqueries attributes $100 $200 $300 $400 $500 $100 $200 $300 $400...
TRANSCRIPT
Data BitsMany to Many
Subkeys Joins Queries Attributes Attributes
$100
$200
$300
$400
$500
$100 $100 $100 $100
$200 $200 $200 $200
$300 $300 $300 $300
$400 $400 $400 $400
$500 $500 $500 $500
Final DataBit
$100 Answer from Many-to-Many
This represents a specific modeling situation that you might encounter
frequently in database design. .
$100 Question from Many-to-Many
What is a design pattern?
$200 Answer from Many-to-Many
This class contains attributes which are the properties of an
association.
$200 Question from Many-to-Many
What is an association class?
$300 Answer from Many-to-Many
This association has a maximum multiplicity of "*" on both sides.
$300 Question from Many-to-Many
What is a many-to-many association?
$400 Answer from Many-to-Many
This attribute can be computed from data stored elsewhere in the database;
it is shown in UML but not in the relation scheme.
$400 Question from Many-to-Many
What is a derived attribute?
$500 Answer from Many-to-Many
This table is created to hold the linking attributes (FKs) from both sides of a
many-to-many association, whether or not there is an association class.
$500 Question from Many-to-Many
What is a junction table?
$100 Answer from Subkeys
This is the formal definition of the super key property; if I know the value of set
"X" of attributes in a relation, I can uniquely determine the value of set "Y"
(as well as X).
$100 Question from Subkeys
What is a functional dependency?
$200 Answer from Subkeys
This set of attributes is a super key for some, but not all, of the attributes in a
relation.
$200 Question from Subkeys
What is a subkey?
$300 Answer from Subkeys
This decomposition of a relation scheme eliminates a subkey and lets
us recreate the original scheme’s information with the join in a query.
$300 Question from Subkeys
What is lossless join decomposition?
$400 Answer from Subkeys
Following this set of rules insures that a database is well designed.
$400 Question from Subkeys
What is normalization?
$500 Answer from Subkeys
A database with no subkey in any relation (with rare exceptions) is said to
be in this form.
$500 Question from Subkeys
What is third normal form?
$100 Answer from Joins
Join of two tables with the intersection of their schemes used as join
attributes.
$100 Question from Joins
What is a natural join?
$200 Answer from Joins
Join of two tables with join attributes specified by the programmer.
$200 Question from Joins
What is an inner join?
$300 Answer from Joins
Join of two tables that retains unmatched join attributes from one or
both sides.
$300 Question from Joins
What is an outer join?
$400 Answer from Joins
Paste of every pair of tuples from each relation, disregarding join attributes. Also know as a Cartesian product.
$400 Question from Joins
What is a cross join?
$500 Answer from Joins
An alternate, short name for a table in the FROM clause of a SELECT
statement.
$500 Question from Joins
What is an alias?
$100 Answer from Queries
This language is used to build and manipulate relational databases. It is declarative, rather than procedural.
$100 Question from Queries
What is the Structured Query Language (SQL)?
$200 Answer from Queries
Statements to create and modify tables and other database objects.
$200 Question from Queries
What is Data Definition Language (DDL)?
$300 Answer from Queries
Statements to work with data in a table.
$300 Question from Queries
What is Data Manipulation Language (DML)?
$400 Answer from Queries
Clause used when you combine single columns with an aggregate
function.
$400 Question from Queries
What is a Group By Clause?
$500 Answer from Queries
Function that operates on a group of rows, for example, SUM.
$500 Question from Queries
What is an Aggregate Function?
$100 Answer from Attribute Attribute
This is considered a class within a class.
$100 Question from Attribute Attribute
What is a weak entity?
$200 Answer from Attribute Attribute
There are many distinct values entered for this in the same column of the table.
$200 Question from Attribute Attribute
What is a multi-valued attribute?
$300 Answer from Attribute Attribute
This causes a large number of null values in a table row.
$300 Question from Attribute Attribute
What is a repeated attribute?
$400 Answer from Attribute Attribute
[0..*]
$400 Question from Attribute Attribute
What is the UML notation to show a repeating or multi-valued attribute?
$500 Answer from Attribute Attribute
You would only do this when the repeated attribute has several
attributes of its own.
$500 Question from Attribute Attribute
What is show the repeating attribute in its own class?
Final DataBitKeys
An outside agency such as a standards body or a government agency has
developed this so that we can use it as if it were a descriptive attribute.
Final DataBit
What is an external (surrogate) key?