01. Which two statements are true about aggregate functions?
a) COUNT (distinct) returns a count of the number of rows with different values including Null.
b) MAX () returns null if there are no rows to aggregate.
c) AVG () does not allow use of the distinct option.
d) SUM () returns o if there are no rows to aggregate.
e) MIN () cannot use distinct when it executes as a Windows function.
02. What is the advantage of using a data-driven approach in application development?
a) It improves the accuracy and reliability of the application's behavior
b) It reduces the amount of data needed to run the application
c) It eliminates the need for programming languages in application development
d) It allows for more complex functionality to be implemented in the application
03. How can transactions be controlled in SQL?
a) By using the BEGIN TRANSACTION statement
b) By using the COMMIT statement to save changes to the database
c) By using the ROLLBACK statement to undo changes to the database
d) All of the above
04. You are using buffered queries with PHP mysqli in a browser-based web application. Which three are true?
a) Additional queries on the same session are blocked until the result set is released.
b) Results are sent to the calling PHP process for buffering.
c) Buffered queries must be explicitly enabled using mysqliuseresult.
d) Large results can have a negative impact on performance.
e) Results are sent from the server to the browser for buffering.
f) Buffered queries are enabled by default.
g) Buffered queries should be used on large tables when the result size is unknown.
05. What are the benefits of using a document store in MySQL?
a) Improved scalability by allowing for horizontal scaling and sharding of data
b) Improved performance by reducing the need for joins and improving data locality
c) Improved flexibility by allowing for schema-less data storage
d) All of the above
06. How can queries be rewritten for optimization in MySQL?
a) By breaking complex queries into simpler ones
b) By using subqueries instead of joins
c) By reducing the number of columns returned in the SELECT clause
d) All of the above
07. Which of the following statements is true about using a connector to retrieve data from a database?
a) It is not possible to retrieve data from a database using a connector
b) It is only possible to retrieve data from a database using SQL queries
c) A connector simplifies the process of retrieving data from a database
d) Retrieving data from a database using a connector is slower than using SQL queries
08. You must enforce data integrity for data Inserted in a JSON column. Which statement successfully creates a constraint in a 3SON column?
a) CREATE TABLE fshop (id INT NOT NULL AUTO_ INCREMENT, product JSON, CHECK (id>0) ) ENGXNE=InnoDB;
b) CREATE TABLE fshop ( product JSON, f INT' GENERATED ALWAYS AS (product->"S - id") ) ;
c) CREATE TABLE fshop (id INT NOT NULL AUTOINCREMENT, product JSON, PRIMARY KEY (id)) ENGINE=InnoDB;
d) CREATE TABLE fshop (product JSON CHECK (JSON_VALID(product) ) ) ;
09. Which two are true about indexes?
a) Secondary index access will always be faster than a table scan.
b) Indexes reduce disk space used.
c) Indexes are used to enforce unique constraints.
d) Indexing all of a table's columns improves performance.
e) Indexes contain rows sorted by key values.
10. How can a document store be created and accessed in MySQL?
a) By creating a new database and enabling the document store feature
b) By using the CREATE COLLECTION statement to create a document store
c) By using the X DevAPI to access the document store
d) All of the above
The Oracle MySQL 8.0 Database Developer (1Z0-909) Sample Question Set is designed to help you prepare for the MySQL 8.0 Database Developer Oracle Certified Professional certification exam. To become familiar with the actual Oracle Certification exam environment, we suggest you try our Sample Oracle 1Z0-909 Certification Practice Exam.