1) The practical significance of taking the logical view of a database is that is serves as reminder of the simple file concept of data storage.
2) You can think of a table as a persistent representation of a logical relation.
3) Because the relational model uses attribute values to establish relationships among tables, many data-base susers correctly assume that the term relation refers to such relationships.
4) The order of the rows and columns is important to the DBMS.
5) Numeric data are data on which you can perform meaningful arithmetic procedures.
6) Character data can contain any character or symbol intended for mathematical manipulation.
7) Each table in a relational database must have a primary key.
8) The idea of determination is unique to the database environment.
9) In a relational model, if A determines B, C, and D, you write A = B, C, D.
10) Only a single attribute, not multiple attributes, can define functional dependence.
11) If the attribute (B) is functionally dependent on a composite key (A) but not on any subset of that composite key, the attribute (B) is fully functionally dependent on (A).
12) A null is created when you press the Enter key or the Tab key to move to the next entry without making a prior entry of any kind.
13) There is never a good reason to use null values in a database.
14) Depending on the sophistication of the application development software, nulls can create problems when functions such as COUNT, AVERAGE, and SUM are used.
15) Tables within a database share common attributes that enable the tables to be linked together.
16) A foreign key must exist in both tables that have a relationship
17) RDBMSs enforce integrity rules automatically.
18) Referential and entity integrity are two names for the same thing.
19) The SELECT operator yields a vertical subset of a table.
20) Tables must have the same attribute characteristics (the columns and domains must be compatible) to be used in a UNION.
21) The DIFFERENCE operator subtracts one table from the other.
22) In a natural join, the column on which the join was made occurs twice in the new table.
23) A left outer join on tables CUSTOMER and AGENT yields all of the rows in the CUSTOMER table, including those that do not have a matching value in the AGENT table.
24) The DIVIDE operation uses one single-column table (e.g., column "a") as the divsor and one two-column table (e.g., columns "a" and "b") as the dividend.
25) A data dictionary contains metadata-data about data.
26) A data dictionary is sometimes described as :the database designer's database" because it records the design decisions about tables and their structures.
27) Current relational database software generally provides only a system catalog (and not a data dictionary).
28) The one-to-many (1:M) relationship is easily implemented in the relational mode by putting the foreign key of the "1" side in the table of the "many" side as a primary key.
29) As rare as 1:! relationships should be, certain conditions absolutely require their use.
30) DBMSs use indexes for many different purposes.
