In the database/sql package, what method is used to execute a SQL query that returns rows?
- Query
- Execute
- ExecuteQuery
- Fetch
The correct option is Query. In Go's database/sql package, the Query method is used to execute a SQL query that returns rows from the database. This method is commonly used for SELECT queries.
What does the '==' operator do in Go when used with slices?
- Checks if both slices point to the same underlying array
- Compares the elements of the slices
- Compares the lengths of the slices
- It is not a valid operator to use with slices in Go
The '==' operator in Go when used with slices checks if both slices point to the same underlying array. It does not compare the elements or the lengths of the slices, only the reference to the underlying array.
You're debugging a program and encounter a segmentation fault error. What could be a potential cause of this error related to pointers in Go?
- Dereferencing a nil pointer
- Incorrect use of pointer arithmetic
- Memory leak due to unreleased pointers
- Stack overflow caused by excessive pointer usage
Dereferencing a nil pointer is a common cause of segmentation fault errors in Go. When you attempt to access or modify the value pointed to by a nil pointer, it results in a runtime panic, leading to a segmentation fault. It's essential to check for nil pointers before dereferencing them to avoid such errors.
You're designing a system where you need to represent various shapes. How would you use structs in Go to model this?
- Define a struct for each shape, such as Rectangle, Circle, Triangle, etc., with fields representing their attributes like width, height, radius, etc.
- Use a map with string keys representing shape names and interface{} values representing shape attributes, allowing for dynamic addition of new shapes.
- Use a single struct named Shape with a field to identify the type of shape and additional fields representing attributes, which might result in a less clear and more complex design.
- Use an interface named Shape with methods like Area() and Perimeter() and then define separate structs like Rectangle, Circle, Triangle implementing this interface.
Defining a struct for each shape with specific fields provides a clear and structured way to represent different shapes in the system, facilitating ease of use and maintenance. It follows the principle of composition, where each struct represents a distinct entity with its own attributes and behaviors.
The _______ operator in Go is used to access struct fields.
- Arrow
- Colon
- Dot
- Slash
In Go, the dot operator (.) is used to access fields and methods of a struct. It allows programmers to retrieve and manipulate the data stored within a struct instance. The dot operator is fundamental for working with struct types in Go.
In Go, what is the purpose of the json:"fieldname" tag in struct fields?
- Adds metadata for JSON encoding and decoding
- Defines the field's default value
- Indicates the field's visibility
- Specifies the field type
The json:"fieldname" tag in Go struct fields is used to provide metadata for JSON encoding and decoding. It allows developers to specify the JSON field name corresponding to the struct field. This is particularly useful when the JSON representation needs to differ from the Go struct's field names. For example, you can use it to control the JSON key naming conventions or to map struct fields to specific JSON fields.
To achieve meaningful code coverage results, it's essential to have a _______ test suite.
- Basic
- Comprehensive
- Limited
- Randomized
Comprehensive
The '_______' function in Go is often used in conjunction with 'panic()' to handle unexpected errors gracefully.
- catch()
- handle()
- recover()
- resume()
In Go, the 'recover()' function is used to regain control of a goroutine that is panicking. It should be deferred immediately after the 'defer' statement, and when a panic occurs, it stops the panic and returns the value passed to 'panic()'. This is commonly used to handle unexpected errors gracefully and prevent the program from crashing.
How can you determine the type of an interface value in Go?
- Using the interface{} keyword
- Using the reflect package
- Using the switch statement
- Using the type assertion
In Go, you can determine the type of an interface value using a type assertion. This involves using the syntax value.(Type) where value is the interface variable and Type is the desired type you want to assert. If the assertion is successful, it returns the underlying value and a boolean indicating success. Otherwise, it triggers a panic. This method allows you to safely work with interface values by checking their types dynamically.
What is the purpose of using transactions in database management systems?
- To encrypt sensitive data
- To enforce access control
- To ensure data consistency and integrity
- To improve database performance
Transactions in database management systems serve the purpose of ensuring data consistency and integrity. By grouping operations together as a single unit, transactions help maintain the integrity of the data by either applying all the operations successfully or rolling back the changes if an error occurs. This ensures that the database remains in a consistent state, even in the event of failures or concurrent access by multiple users.