The handy significance of acquisition the logical view of a database is that it serves together a reminder of the simple document concept the data storage.
You can think that a table as a persistent depiction of a reasonable relation.
Because the relational design uses attribute worths to create relationships amongst tables, many database users appropriately assume the the term relation describes such relationships.
The stimulate of the rows and also columns is essential to the DBMS.
Numeric data are data on i beg your pardon you can perform meaningful arithmetic procedures.
Character data deserve to contain any type of character or symbol intended for mathematical manipulation.
Each table in a relational database must have actually a main key.
A appropriate understanding of the concept and use of secrets in a relational database version is very important.
If A identify B, C, and also D, you create A = B, C, D.
Only a single attribute, not multiple attributes, defines functional dependence.
If the attribute (B) is functionally dependency on a composite an essential (A) however not on any kind of subset of that composite key, the attribute (B) is totally functionally dependency on (A).
A null is developed when you push the Enter an essential or the Tab vital to move to the next entry without making a front entry of any kind of kind.
There is never a good reason to use null worths in a database.
Depending on the sophistication the the application development software, nulls can develop problems when functions such together COUNT, AVERAGE, and SUM are used.
Tables in ~ a database re-superstructure common features that allow the tables come be linked together.
A foreign key must exist in both tables that have actually a relationship.
All RDBMSs obtrude integrity rules automatically.
Referential and entity integrity are two names for the very same thing.
Tables must have actually the exact same attribute attributes (the columns and also domains need to be identical) come be provided in a UNION.
The distinction operator subtracts one table native the other.
The choose operator returns a upright subset that a table.
In a herbal join, the pillar on i m sorry the join was make occurs double in the new table.
A left outer sign up with on tables CUSTOMER and AGENT yields every one of the rows in the customer table, consisting of those that do not have actually a corresponding value in the agent table.
The division operation supplies one single-column table (i.e. Obelisk "a") as the divisor and one two-column table (i.e. Columns "a" and also "b") together the dividend.
A data dictionary includes metadata—data around data.
A data dictionary is sometimes described as "the database designer’s database" due to the fact that it documents the architecture decisions around tables and their structures.
Current relational database software typically provides only a system brochure (and not a data dictionary).
The one-to-many (1:M) partnership is quickly implemented in the relational design by putting the foreign an essential of the "1" next in the table that the "many" side together a major key.
As rare together 1:1 relationships must be, details conditions absolutely require their use.
DBMSs usage indexes for numerous different purposes.
____ logic, used extensively in mathematics, gives a structure in which an delinquent (statement the fact) have the right to be showed as one of two people true or false. A. Property b. Database c. Relational d. Index
The relational database model allows you to see data ____ rather than ____. A. Relationally, hierarchically b. Hierarchically, relationally c. Physically, logically d. Logically, physically
d. Logically, physically
The relational model’s creator, E. F. Codd, offered the hatchet relation as a synonym for ____. A. Table of contents b. Crucial c. Table d. Reationship
A(n) ____ is perceived as a two-dimensional structure composed the rows and columns. A. Table b. Rowset c. Attribute d. Intersection
Date attributes contain calendar days stored in a special layout known together the ____ date format. A. Epoch b. Calendar c. Julian d. Logical
____ data deserve to have just a true or false (yes or no) condition. A. Logical b. Character c. Date d. Numeric
In the relational model, ____ are important due to the fact that they are supplied to ensure the each row in a table is uniquely identifiable. A. Relations b. Secrets c. Indexes d. Logical structures
In the paper definition of a database table, the statement "A ____ B" indicates that if you know the value of attribute A, you can look up the value of attribute B. A. Consists of b. Is related to c. Owns d. Determines
The attribute B is ____ the attribute A if each value in tower A determines one and also only one worth in pillar B. A. Logically dependent on b. Owned by c. Established by d. Functionally dependency on
d. Functionally dependency on
Any attribute the is part of a vital is known as a ____. A. Crucial attribute b. Logical attribute c. Key determiner d. Selector
a. Key attribute
If the attribute (B) is functionally dependent on a composite an essential (A) yet not on any kind of subset of that ____ key, the attribute (B) is totally functionally dependent on (A). A. Foreign b. Unique c. Composite d. Complete
A ____ is any an essential that unique identifies each row. A. Superkey b. One-of-a-kind c. Selective d. Candidate
No data entry at all is well-known as a(n) ____. A. Nil b. Null c. Empty d. Zero
Controlled ____ renders a relational database work. A. Relationships b. Reasonable c. Chaos d. Redundancy
A ____ is a textual depiction of the database tables wherein each table is provided by that is name followed by the perform of its qualities in parentheses. A. Relational thesaurus b. Reasonable schema c. Relational schema d. Data dictionary
c. Relational schema
In the complying with table description, ____ is the primary key. PRODUCT (PROD_CODE, PROD_DESCRIPT, PROD_PRICE, PROD_ON_HAND, VEND_CODE) a. PROD_DESCRIPT b. PROD_CODE c. PROD_PRICE d. PROD_ON_HAND
Referential ____ means that if the foreign vital contains a value, the value describes an existing precious tuple (row) in an additional relation. A. Integrity b. Uniqueness c. Direction d. Relations
A ____ an essential is identified as a crucial that is provided strictly for data retrieval purposes. A. Lookup b. Foreign c. Candidate d. Secondary
A ____ vital is a minimal (irreducible) superkey. A. Secondary b. Candidate c. Main d. Foreign
All primary crucial entries room unique, and also no part of a primary vital may it is in ____. A. Zero b. A foreign key c. Null d. A candidate key
A customer table’s primary an essential is CUS_CODE. The customer primary vital column has no null entries, and all entries are unique. This is an instance of ____ integrity. A. Reality b. Referential c. Finish d. Null
The ____ constraint have the right to be inserted on a tower to ensure the every row in the table has actually a worth for that column. A. Has VALUE b. No NULL c. MUST have actually VALUE d. No EMPTY
b. Not NUL
To be thought about minimally relational, the DBMS should support the an essential relational operator ____, PROJECT, and JOIN. A. Crossing b. UNION c. Difference d. SELECT
____ combines all rows from two tables, excluding duplicate rows. A. Crossing b. UNION c. Difference d. SELECT
____ yields just the rows that appear in both tables. A. Intersect b. UNION c. Distinction d. SELECT
____, likewise known as RESTRICT, yields values for all rows uncovered in a table that satisfy a offered condition. A. Crossing b. UNION c. Distinction d. SELECT
____ yields a vertical subset that a table. A. Task b. Select c. UNION d. DIFFERENCE
A(n) ____ sign up with links tables by choosing only the rows with typical values in their typical attribute(s). A. Equal b. Distinctive c. International d. Natural
The equijoin takes its surname from the to compare operator ____ provided in the condition. A. * b. c. = d. >
In an external join, the suitable pairs would certainly be retained and also any unmatched values in the other table would certainly be left ____. A. In one more table b. Null c. The end of the results d. With matching values native the initial table
A ____ consists of at least all of the attribute names and characteristics because that each table in the system. A. Data thesaurus b. Relational schema c. Reasonable schema d. Join
a. Data dictionary
The ____ is in reality a system-created database whose tables keep the user/designer-created database characteristics and contents. A. Meta dictionary b. Schema c. Data dictionary d. Mechanism catalog
d. Device catalog
In a database context, words ____ indicates the usage of the same attribute surname to label various attributes. A. Redundancy b. Homonym c. Duplicate d. Synonym
In a database context, a(n) ____ shows the use of different names to define the same attribute. A. Entity b. Duplicate c. Synonym d. Homonym
____ relational form is the "relational ideal." a. 1:1 b. 1:M c. M:1 d. M:N
The ____ relationship need to be rare in any kind of relational database design. A. 1:1 b. 1:M c. M:1 d. M:N
Since it is offered to attach the tables that originally were related in a M:N relationship, the composite entity structure includes—as international keys—at least the ____ secrets of the tables that space to be linked. A. Composite b. At sight c. Primary d. Unique
A(n) ____ is an ordered plan of keys and also pointers. A. Table b. Superkey c. Connection d. Index
When you specify a table’s major key, the DBMS automatically creates a(n) ____ index on the primary crucial column(s) girlfriend declared. A. Key b. Incomplete c. Distinct d. Primary
Codd’s preeminence of ____ states: application programs and ad hoc framework are logically unaffected when alters are made come the table frameworks that maintain the original table values (changing order of pillar or inserting columns). A. Nonsubversion b. Logical Data self-reliance c. Substantial Data Sublanguage d. Integrity Independence
b. Reasonable Data Independence
The logical check out of the relational database is facilitated by the creation of data relationships based upon a reasonable construct well-known as a(n) ____________________.
In the relational model, ____________________ room important due to the fact that they are offered to ensure that each row in a table is unique identifiable.
Attribute A identify attribute B (that is, B is functionally ____________________ on A) if all of the rows in the table that agree in worth for attribute A additionally agree in value for attribute B.
A(n) ____________________ key can be described as a superkey there is no unnecessary attributes.
If the foreign crucial contains either corresponding values or nulls, the table that makes use of that foreign key is said to exhibition ____________________ integrity
The following example exhibits ____________________ integrity: The customer table’s primary an essential is CUS_CODE. The client primary key column has no null entries, and all entries room unique. Similarly, the agent table’s primary key is AGENT_CODE, and also this primary an essential column also is free of null entries.
To protect against nulls, some developers use unique codes, known as ____________________, to show the lack of part value.
The relational operators have the property of ____________________; the is, the use of relational algebra operators on currently tables (relations) produces new relations.
PRODUCT yields all possible pairs that rows from two tables—also recognized as the ____________________ product.
____________________ is the genuine power behind the relational database, allowing the use of live independence tables linked by typical attributes.
A(n) ____________________ links tables top top the basis of an equality condition that compares mentioned columns of every table.
____________________ joins room especially helpful when you are trying to recognize what value(s) in connected tables cause(s) referential integrity problems.
A(n) ____________________ gives a detailed summary of every tables found within the user/designer-created database.
The ____________________ catalog can be defined as a detailed system data thesaurus that explains all objects in ~ the database, including data around table names, the table’s creator and creation date, the variety of columns in each table, the data form corresponding to each column, table of contents filenames, table of contents creators, authorized users, and accessibility privileges.
The ____________________ relationship is the relational database norm.
If one room chair—a professor—can chair just one department and one department can have only one room chair, then the reality PROFESSOR and also DEPARTMENT exhibition a(n) ____________________ relationship.
____________________ relationships deserve to be applied by creating a brand-new entity in 1:M relationships v the original entities.
Fortunately, the troubles inherent in the ____________________ relationship can quickly be avoided by producing a composite entity.
The suitable use the ____________________ secrets is an important to regulating data redundancy.
Proper data ____________________ design requires closely defined and controlled data redundancies to duty properly.
A(n) ____________________ is one orderly arrangement used to logically access rows in a table.
A(n) ____________________ index is an table of contents in i m sorry the index key can have only one pointer value (row) associated with it.
The index an essential can have multiple attributes, this is called a(n) ____________________ index.
Codd’s ascendancy of ____________________ claims that every value in a table is guarantee to be available through a mix of table name, primary an essential value, and column name.