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TEST BORRADO, QUIZÁS LE INTERESEDAW1 Bases de Datos U1 U2

COMENTARIOS ESTADÍSTICAS RÉCORDS
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Título del test:
DAW1 Bases de Datos U1 U2

Descripción:
English Test

Autor:
AVATAR

Fecha de Creación:
29/10/2023

Categoría:
Informática

Número preguntas: 59
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Temario:
Which of the following characteristics must a relation meet in the relational model? Select one or more: Each attribute has a different name in each table and in different tables. Each table has a different name in the same database. The order of the tuples does not matter. All data for an attribute must be from the same domain.
Which of the following fields could be primary keys? Select one: Telephone Address NIF Name.
DROP TABLE EMPLEADOS... Select one: Delete the table structure but not the data. Create the Employees table. Delete all records and table structure. Delete all records from the Employees table.
In the instruction, DROP USER NombreUsuario CASCADE;what is the option for CASCADE? Select one: Prevents that user from being deleted. Create the user with CASCADE permission. It is used to remove that user's name from the database. Delete all the user's objects before deleting them.
Keys that are an attribute or set of attributes of a relation whose values ​​coincide with the values ​​of the primary key of some other relation (or the same) are called: Select one or more: Secondary Primary Foreign External.
The statement to modify the definition of a database object is: Select one: ALTER CREATE DROP DELETE.
The statement REVOKE is used to: Select one: Assign Permissions. Create database objects. Modify permissions. Deny permissions.
Data validation restrictions are made with: Select one: ADD CONSTRAINT PRIMARY KEY.... ADD CONSTRAINT FOREIGN KEY.... ADD CONSTRAINT CHECK.... ADD CONSTRAINT DEFAULT....
Restrictions on non-repeated values ​​are done with: Select one: ADD CONSTRAINT FOREIGN KEY.... ADD CONSTRAINT CHECK.... ADD CONSTRAINT PRIMARY KEY.... ADD CONSTRAINT UNIQUE....
The default value restrictions are: Select one: ADD CONSTRAINT PRIMARY KEY.... ADD CONSTRAINT FOREIGN KEY.... ADD CONSTRAINT CHECK.... ADD CONSTRAINT DEFAULT....
The restrictions that relate one table to another are: Select one: ADD CONSTRAINT CHECK.... ADD CONSTRAINT FOREIGN KEY.... ADD CONSTRAINT DEFAULT.... ADD CONSTRAINT PRIMARY KEY....
We will call _____ the number of tuples or rows in a relation or table. Select one: Grade Relation Cardinality Entity.
We will call the size of a table _____ based on its number of attributes. Select one: Cardinality Grade Entity Relationship.
To add a restriction to an already created table the statement is: Select one: ALTER TABLE NombreTabla ADD COLUMN CREATE CONSTRAINT NombreRestriccion TO NombreTabla ALTER TABLE NombreTabla ALTER CONSTRAINT ALTER TABLE NombreTabla ADD CONSTRAINT....
To delete a table from the database we will use the instruction: Select one: DROP REVOKE DELETE ALTER.
What is incorrect in the following SQL command?: CREATE TABLE Persona ( Nombre VARCHAR (10), NIF VARCHAR(9) PRIMARY KEY, Profesion VARCHAR(50)) Accent is missing in the profession field. NIF cannot be a primary key. NIF is not VARCHAR data type. Semicolon at the end is missing.
What does this SQL statement do? REVOKE DROP USER FROM Carlos; Select one: Allows Carlos to delete users. Delete the user Carlos. Delete the table named Carlos. Remove Carlos's permission to delete users.
What does the following SQL statement do? GRANT CONNECT TO Sonia; Select one: Prevents Sonia from accessing the database. Remove Sonia from the connection. Deny Sonia the role Connectand all the privileges that this role has associated with it. Grant Sonia the role of Connectwith all the privileges that this role has associated with it.
What does the following SQL statement do? RENAME NombreViejo TO NombreNuevo; Select one: Change the name of a constraint. Change the name of a table. Change the name of a user. Change the name of a field.
What are tuples? Select one or more: Entities Set of columns. Every element of a relationship. Each row of a table.
Views that store the data they display in addition to saving the query that created them are called _____. It's like a photograph of the relationship. Select one: Snapshots Views Base Relation.
A primary key: Select one: It is superkey. It can be repeated. May contain null values. It is an alternative key.
What can a relation have? Select one: Only cardinality. Only attributes. Only grades. Attributes, grade and cardinality.
When creating a table, all its fields must be created. True or false? True False .
The Data Definition language describes data structures and integrity constraints. True or false? True False.
The Data Manipulation language is used to describe data manipulation operations. True or false? True False.
Conceptual data models are those that describe data structures and integrity constraints. True or false? True False.
An index is a data structure that allows access to different rows of the same table through a field or fields. True or false? True False.
NULL value is the same as ZERO. True or false? True False .
NULL value is the same as BLANK SPACE. True or false? True False .
Which of the following is not a permanent file type? Select one: Constant Historical Maneuver Master.
Which of the following is not a type of documentary database? Select one: Full text databases. Reference databases. Electronic image files. Directories.
Which of the following free database management systems is written in Java? Select one: PostgreSQL MySQL SQLite Apache Derby.
Which of the following database management systems is not commercial? Select one: Foxpro DB2 Firebird Informix.
Within the functions of database management systems, the description function is performed through the language: Select one: DCL DDL DML SCL.
The place where the information about all the data that make up the database is deposited and that contains the logical characteristics of the structures that store the data, their name, description, content and organization, is called: Select one: Database manager. Data Dictionary. Metadata. DDL.
The level at which the physical structure of the database is described, through an internal schema in charge of detailing the database storage system and its access methods, is: Select one: External level. Conceptual level. Internal level. Logical level.
The percentage of records consulted or modified in each file treatment, with respect to the total number of records contained in it, is called: Select one: Renewal rate Query or modification rate Renewal frequency Consultation frequency.
In the relational database model, tables must meet a series of requirements. Which of the following is not correct? Select one: All fields are of the same type. There are no duplicate records. The table can only have one type of record. There are no repeated fields or attributes.
The amount of information that is transferred between the medium on which the file is stored and the secondary memory of the computer, in a single read/write operation, is called: Select one: Logical record Neither answer is correct, since the transfer is done with main memory Blocking factor Physical record.
In sequential files, the file opening mode conditions: Select one: No answer is correct. Reading or writing. Reading Writing.
In a database, those in charge of carrying out the identification of the data, the relationships between them, their restrictions, etc. they will be: Select one: Designers Programmers Administrator End users.
Normally, in each read/write operation, several records of the file are transferred, that is, a _____ and it usually contains several logical records. Select one: Block Archive Field Record.
To briefly name a network mass storage system, we use the acronym: Select one: SAN ASN RAID NAS.
A file or archive is made up of: _____, which contain data related to the same element or object. Select one: Logical fields Logical records Lines Values.
A SAN corresponds to: Select one: A storage area network. A massive network storage system. A stored network system. An array of independent redundant disks.
The set of values ​​that a certain attribute can take is called a domain. True or false? True False.
The number of physical registers that enter a logical register is known as the blocking factor. True or false? True False .
The type of files that store application data that cannot be kept in main memory due to lack of space are called intermediate files. True or false? True False .
During its design, a relational database goes through a process known as database normalization. True or false? True False.
The usual language for building relational database queries is DDL . True or false? True False .
The language that provides statements to perform DDL, DML, and DCL operations is SQL . True or false? True False.
In direct access files, those in which the physical address of a record is obtained through a mathematical transformation in which the key intervenes, are called Indexed Direct Access Files. True or false? True False .
In direct access files, a record can be accessed by indicating its relative position within the file or through a key that is part of the record as another field. True or false? True False.
In sequential files there is usually a mark indicating the end of the file, which is usually called EOF . True or false? True False.
A description of the data is also stored in a database, this is what is called metadata, it is stored in the catalog and is what allows logical-physical data independence to exist. True or false? True False.
The visual form of the hierarchical database model is a tree, at the bottom are the parents and at the top are the children. True or false? True False .
The records are divided into fields that contain each of the basic information that makes up a record. True or false? True False.
For a database, there will only be a single external schema, a single conceptual schema, and there could be several internal schemas defined for one or more users. True or false? True False .
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