WSI Flashcards
Which of the following are database models?
Bohr’s model
Relational model
Hierarchical model
Catalog model
Relational model
Hierarchical model
Which of the following attributes can be placed on the Student entity in the relational model:
PESEL
Numbers of all groups
Date of birth
Student’s Subjects
PESEL
Date of birth
Which of the following are data models:
Network model
Bohr’s model
Object model
The card model
Network model
Object model
The card model
Which of the following statements is true?
NULL = NULL has the logical value NULL
NULL <> NULL has the logical value TRUE
NULL <> NULL has the logical value NULL
NULL = NULL has the logical value FALSE
NULL = NULL has the logical value NULL
NULL <> NULL has the logical value NULL
The SELECT statement is used to:
fetching records from the database
inserting records into the database
deleting records from the database
updating records in the database
fetching records from the database
- (0)
Edgar Codd
Bill Gates
Niels Bohr
Alan Turing
Edgar Codd
Select the correct statements regarding indexes in database servers:
The programmer must specify in the SQL query that the index is to be used
When an index is installed on the table, the query will always execute faster
The index is necessary to be able to update the data
When an index is placed on the table, the query can be executed faster
When an index is placed on the table, the query can be executed faster
Which of the following statements are true?
The SQL INSERT statement is used to delete data from the database.
The INSERT SQL statement is used to modify data in the database.
The INSERT SQL statement is used to insert data into the database.
The SQL INSERT statement is used to read data from the database.
The INSERT SQL statement is used to insert data into the database.
Which of the following statements are true?
The SQL SELECT statement is used to read data from the database.
The SQL SELECT statement is used to insert data into the database.
The SQL SELECT statement is used to delete data from the database.
The SQL SELECT statement is used to update data in the database.
The SQL SELECT statement is used to read data from the database.
Represented in a relational database as a table is
A subset of the Cartesian product
The relationship between database tables
An ordered list of entities
A subset of the Cartesian product
Mark the correct statements
The database server uses a buffer in RAM
each INSERT, DELETE, UPDATE statement is saved immediately after execution in the file containing the table data
each SELECT statement must always retrieve data directly from the hard drive (from which sources in the database the data is to be read)
The database server uses a buffer in RAM
Which of the following attributes can be placed on the MusicAlbum entity in the relational model? Remember that every entity in the relational model must be in first normal form:
AlbumCode
Authors of Works
OpinionsListening
Titles of Songs
AlbumCode
The logical data structure in the relational data model is:
Table structure
List structure
The relational model does not impose any data structure
File structure
Table structure
The relationship is:
represented in a relational database as a table
a subset of the Cartesian product
relationship between database tables
an ordered list of entities
relationship between database tables
The stereotype «extend» means that:
An actor can use another actor’s use cases
An actor can use a specific use case
One use case is a mandatory part of another
One use case is an optional part of another
One use case is an optional part of another
Inheritance is:
a relationship between classes that connects a more general class with a more specialized one
hiding the structure and implementation of the object
generalization of the set of connections between objects
an entity or idea mapped to a programming construct
a relationship between classes that connects a more general class with a more specialized one
Select the correct answer
TRUE AND NULL = NULL
False AND NULL = NULL
TRUE OR NULL = TRUE
TRUE OR NULL = NULL
TRUE AND NULL = NULL
TRUE OR NULL = TRUE
Which of the following statements are true:
The DELET statement of the SQL language is used to modify data in the database.
The DELET statement of SQL language is used to delete data from the database.
The DELET statement of the SQL language is used to insert data into the database.
The SQL DELET statement is used to read data from the database.
The DELET statement of SQL language is used to delete data from the database.
Requirements: a student belongs to one class, one class has many students. How to define tables in the relational model? (this is questions with drawings)
Student Table: StudentID, Name, Surname
Class table: classid, classlevel
Table [something]: classid, studentid
Student Table: StudentID, Name, Surname
Class table: classid, classlevel, studentid
(same as above only tables in reverse order)
Class table: classid, classlevel, studentid
Student Table: StudentID, Name, Surname
Student Table: StudentID, Name, Surname, ClassID
Class table: classid, classlevel
Student Table: StudentID, Name, Surname, ClassID
Class table: classid, classlevel
Mark the correct answers:
NOT NULL= TRUE
TRUE OR NULL=NULL
FALSE AND NULL=NULL
FALSE AND NULL= FALSE
FALSE AND NULL= FALSE
Which of the following statements are true:
The WHERE clause of the SELECT statement in SQL specifies the conditions that the rows being read must meet.
The ORDER BY clause of the SELECT statement in SQL specifies the conditions that must be met by the rows being read.
The WHERE clause of the SELECT statement in SQL determines how the rows read from the database are sorted.
The ORDER BY clause of the SELECT statement in SQL specifies the conditions that must be met by the rows being read.
The WHERE clause of the SELECT statement in SQL specifies the conditions that the rows being read must meet.
Which of the following problems could be the result of technical debt?
None of the above, technical debt is a way to rip off the client
Increase in system implementation costs
Difficulties in implementing more user stories in future sprints
No possibility of further expansion of the system
Increase in system implementation costs
Difficulties in implementing more user stories in future sprints
No possibility of further expansion of the system
Mark the correct answers:
TRUE and NULL = NULL
NOT NULL = NULL
NOT NULL = TRUE
TRUE OR NULL = NULL
TRUE and NULL = NULL
NOT NULL = NULL
Which of the following statements are true about the relational database model?
a foreign key is a unique identifier of a row in a table
in a relational database table, rows can be repeated
There can only be one primary key in a table
There can be several foreign keys in a table
There can only be one primary key in a table
There can be several foreign keys in a table
From the list below, select the properties that characterize a Use Case Actor:
such a concept does not exist
represents a category of users with specific needs and permissions
represents a specific person
may be a special case of another Actor
may be a special case of another Actor
Which of the following attributes can be placed on the Student entity in the relational model? Remember that every entity in the relational model must be in first normal form:
Student subjects
Start date of study
Date of birth
Student Assessment
Start date of study
Date of birth
Select the correct answer:
FALSE AND NULL = FALSE
TRUE OR NULL = NULL
NOT NULL= TRUE
NOT NULL= NULL
FALSE AND NULL = FALSE
NOT NULL= NULL
Which of the following statements are true?
The ORDER BY clause of the SELECT statement in SQL specifies how to sort the rows read from the database.
The FROM clause of the SELECT statement in SQL specifies the conditions that must be met by the rows being read.
The WHERE clause of the SELECT statement in SQL specifies the conditions that must be met by the rows being read.
The ORDER BY clause of the SQL SELECT statement specifies the tables from which data will be read.
The ORDER BY clause of the SELECT statement in SQL specifies how to sort the rows read from the database.
The WHERE clause of the SELECT statement in SQL specifies the conditions that must be met by the rows being read.
Inheritance is:
a description of a group of objects that share the same set of values
an entity or idea mapped to a programming construct
a relationship between actors that connects a more general actor with a more specialized one
generalization of the set of connections between objects
Which of the following statements are true?
NULL <> NULL has the logical value NULL
NULL <> NULL has the logical value FALSE
NULL <> NULL has the logical value TRUE
NULL = NULL has the logical value FALSE
NULL <> NULL has the logical value NULL
Which of the following statements are true in the relational data model (I don’t know the correct answer)
the primary key is a unique identifier for a row in a table
in a relational database table, rows can be repeated
in a relational database, the only logical structure for storing data is tables
a foreign key is a pointer to a row in another table
The primary key is a unique identifier for a row in a table.
In a relational database, the only logical structure for storing data is tables.
A foreign key is a pointer to a row in another table.
Which of the following are data models:
The card model
Network model
Hierarchical model
Object model
The card model
Network model
Hierarchical model
Object model
Which of the following statements are true about the relational data model:
A perspective is a logical structure for storing data.
The perspective is for presentation, not for storing data.
Data from a perspective can be read in the same way as data from tables.
The perspective shows the values read from the database at the time of its launch.
The perspective is for presentation, not for storing data.
Data from a perspective can be read in the same way as data from tables.
The perspective shows the values read from the database at the time of its launch.
From the list below, select the properties that characterize the Use Case Actor.
may be a special case of another actor
such a concept does not exist
represents a specific person
can only be associated with one use case
may be a special case of another actor
Which of the following statements are true?
The UPDATE statement is used to modify data in the database.
The UPDATE statement is used to insert data into the database.
The UPDATE statement is used to read data from the database.
The UPDATE statement is used to delete data in the database.
The UPDATE statement is used to modify data in the database.
