Big Data Technologies test with answers
Replenishment date: 04.10.2023
Contents: Big Data Technologies ANSWERS (1).pdf (288.99 KB)
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Description
1. Which of the following data types are supported in mysql?
*TEXT, BLOB, JSON, CHAR, IMG
*BLOB, CHAR, FLOAT, DOUBLE
*INT, JPEG, BIGINT, DATE, JSON
2. What is the difference between CHAR and VARCHAR data types?
*CHAR stores a fixed-length string of up to 255 characters. If the length of the inserted record is shorter, then MySQL automatically pads the value with spaces. VARCHAR stores variable-length strings up to 65 characters.
*CHAR stores a fixed-length string of up to 255 characters. In this case, any symbols other than alphabetic ones can be used (such as #$%^&*, etc.). VARCHAR stores all kinds of characters, including alphabetic ones.
*CHAR is used to create immutable tables, VARCHAR can be easily transformed and supplemented.
3. What does backup mean?
*Data backup
*Interpretation of the database into a language understandable to a computer
*Creating a new database using a standard template
4. What does database “isolation” mean?
*Ensures that all transactions are performed in isolation. No transaction will affect another transaction. In other words, one transaction will not be able to read the data of a second transaction that has not yet completed.
*A function that can mix all the data during transfer, and then separate it and arrange it in its original form. Used for backup.
*Means that when a transaction is applied, it will remain in the system, even if the database crashed immediately after the transaction was executed. Any changes made by a transaction should remain forever. If the database reported a successful transaction, then it should actually be applied.
5. Where is the best place to use an RDBMS?
*If there is a clear structure (for example a table) that will need to be changed, formatted and other actions performed with it.
*A clear structure is not visible. Structural relationships between objects are not traced.
*Convenient to use on social networks where users, subscriptions, etc. change frequently.
6. Which command removes spaces at the beginning and end of a line?
*DELITE_STR
*trim
*deltrim
7. Name popular relational and non-relational databases.
*Relational - MySQL, NoSQL, PostgreSQL. Non-relational - SQLite
*Relational - MySQL, SQLite, PostgreSQL. Non-relational - NoSQL
*Relational - MySQL, NoSQL. Non-relational - SQLite, PostgreSQL
8. Specify the correct syntax when retrieving data:
*SELECT column_list FROM table_name
*SELECT column_list TO table_name
*FROM table_name SELECT column_list
9. What will this code output?
number = 0
while number ‹ 4:
number +=1
print (number)
*Sequence from 0 to 4
*Sequence from 1 to 3
*Sequence from 1 to 4
10. What command is used to add data to mysql?
*AUTO_INCREMENT
*INSERT
*VALUE
*TEXT, BLOB, JSON, CHAR, IMG
*BLOB, CHAR, FLOAT, DOUBLE
*INT, JPEG, BIGINT, DATE, JSON
2. What is the difference between CHAR and VARCHAR data types?
*CHAR stores a fixed-length string of up to 255 characters. If the length of the inserted record is shorter, then MySQL automatically pads the value with spaces. VARCHAR stores variable-length strings up to 65 characters.
*CHAR stores a fixed-length string of up to 255 characters. In this case, any symbols other than alphabetic ones can be used (such as #$%^&*, etc.). VARCHAR stores all kinds of characters, including alphabetic ones.
*CHAR is used to create immutable tables, VARCHAR can be easily transformed and supplemented.
3. What does backup mean?
*Data backup
*Interpretation of the database into a language understandable to a computer
*Creating a new database using a standard template
4. What does database “isolation” mean?
*Ensures that all transactions are performed in isolation. No transaction will affect another transaction. In other words, one transaction will not be able to read the data of a second transaction that has not yet completed.
*A function that can mix all the data during transfer, and then separate it and arrange it in its original form. Used for backup.
*Means that when a transaction is applied, it will remain in the system, even if the database crashed immediately after the transaction was executed. Any changes made by a transaction should remain forever. If the database reported a successful transaction, then it should actually be applied.
5. Where is the best place to use an RDBMS?
*If there is a clear structure (for example a table) that will need to be changed, formatted and other actions performed with it.
*A clear structure is not visible. Structural relationships between objects are not traced.
*Convenient to use on social networks where users, subscriptions, etc. change frequently.
6. Which command removes spaces at the beginning and end of a line?
*DELITE_STR
*trim
*deltrim
7. Name popular relational and non-relational databases.
*Relational - MySQL, NoSQL, PostgreSQL. Non-relational - SQLite
*Relational - MySQL, SQLite, PostgreSQL. Non-relational - NoSQL
*Relational - MySQL, NoSQL. Non-relational - SQLite, PostgreSQL
8. Specify the correct syntax when retrieving data:
*SELECT column_list FROM table_name
*SELECT column_list TO table_name
*FROM table_name SELECT column_list
9. What will this code output?
number = 0
while number ‹ 4:
number +=1
print (number)
*Sequence from 0 to 4
*Sequence from 1 to 3
*Sequence from 1 to 4
10. What command is used to add data to mysql?
*AUTO_INCREMENT
*INSERT
*VALUE
Additional Information
11. Which command retrieves data?*SELECT
*INSERT
*DELITE
12. What is the difference between RDBMS and NRDBMS?
*Unlike relational DBMSs, non-relational DBMSs do not support SQL queries.
*Non-relational DBMS, unlike relational ones, can store information in tabular form.
*Non-relational databases do not support image and video formats.
13. What is the essence of data normalization in mysql?
*Normalization is a process in which all data is formatted in a visually understandable form.
*The normalization process is to correct common errors that may be made when importing data. In the future, such errors can lead to a failure of the DBMS.
*The essence of normalization is to get rid of data redundancy, i.e., repetition of the same data in several lines.
14. What will happen after applying the method: select reverse ('arbadakarba')?
*Will generate an error because this method only applies to numeric data types.
*abrakadabra
*ARBADAKARBA
15. What is the difference between INNER JOIN, LEFT JOIN and RIGHT JOIN?
*INNER JOIN: Returns rows when there is a match in both tables.
*LEFT JOIN: Returns all rows from the left table, even if there are no matches in the right table.
*RIGHT JOIN: Returns all rows from the right table, even if there are no matches in the left table.
16. How to install MySQL on a computer?
*This system is installed by default in some browsers. You just need to call it on the command line or in the terminal.
*Downloading the MySQL Community program is available only after registration and subscription. After this, installation files are sent to your email, linked only to one specific computer.
*On the official mysql.com page, in the download section, select the communitu version. Next, following the prompts, install in normal mode.
17. What is the difference between FLOAT and DOUBLE data types?
*FLOAT is an integer data type, and DOUBLE is a comma (real numbers) *FLOAT - contains 4 bytes of information, and DOUBLE - 8 bytes.
*FLOAT - contains 8 bytes of information, and DOUBLE - 16 bytes.
18. Using what command can you calculate the length of a string?
*len()
*length()
*count()
19. ACID Definition
*This is the ability of the database to process any type of data
* (Atomicity - atomicity, consistency - consistency, isolation - isolation, durability - durability) is a standard set of properties that guarantee the reliability of the transaction.
*Properties unique to subscription databases only. These properties ensure full format compatibility when transferring data from one database to another.
20. Choose the correct syntax for adding data to mysql:
*INSERT [ ] table_name [(column_list)] VALUES (value1, value2, ... valueN)
*INSERT [INTO] table_name [(column_list)] VALUES (value1, value2, ... valueN)
*INSERT (into) table_name [(column_list)] VALUES (value1, value2, ... valueN)
21. What is TIMESTAMP format?
*Date and time. Stored as the number of seconds that have passed since January 1, 1970 GMT. Takes up half the space of the DATETIME type. But the range is limited to values from 1970-01-01 00:00:01 to 2038-01-09 03:14:07
*Date and time in YYYY-MM-DD HH:MM:SS format. Valid values are from 1000-01-01 00:00:00 to 9999-12-31 23:59:59
*Only year in YYYY or YY format. Valid values are from 1901 to 2155 or from 70 to 69 (1970 - 2069)
22. What is the difference between CHAR and VARCHAR data types?
*CHAR stores a fixed-length string of up to 255 characters. If the length of the inserted record is shorter, then MySQL automatically pads the value with spaces. VARCHAR stores variable-length strings up to 65 characters.
*CHAR stores a fixed-length string of up to 255 characters. In this case, any symbols other than alphabetic ones can be used (such as #$%^&*, etc.). VARCHAR stores all kinds of characters, including alphabetic ones.
*CHAR is used to create immutable tables, VARCHAR can be easily transformed and supplemented.