To perform CRUD operations with LINQ to SQL, you need to define a ___________.
- DataContext
- SqlConnection
- SqlCommand
- DataAdapter
The correct option is 'DataContext'. In LINQ to SQL, the DataContext class is responsible for connecting to the database and managing the objects retrieved from it. It acts as a bridge between the database and the .NET objects, allowing you to perform Create, Read, Update, and Delete (CRUD) operations on the database using LINQ queries and methods.
In ADO.NET, what is the role of parameters in non-query commands?
- Define command type
- Execute the command
- Handle errors
- Provide values
Parameters in non-query commands of ADO.NET are used to provide values dynamically to the command, helping in executing parameterized queries to interact with the database securely and efficiently.
In Entity Framework, what is the difference between Table Splitting and Entity Splitting when it comes to mapping entities to tables?
- Entity Splitting involves mapping a single entity to multiple tables based on its properties.
- Entity Splitting involves mapping multiple entities to a single table based on their properties.
- Table Splitting involves mapping a single entity to multiple tables based on its properties.
- Table Splitting involves mapping multiple entities to a single table based on their properties.
Table Splitting in Entity Framework allows an entity to be mapped to multiple tables with a one-to-one relationship, where each table represents a subset of the entity's properties. This is useful when dealing with large entities or when certain properties should be stored separately for optimization purposes. Entity Splitting, on the other hand, involves mapping a single entity to multiple tables based on its properties, but with each table containing different sets of properties belonging to the same entity. This allows for more granular control over the database schema and can be beneficial in scenarios where certain properties are rarely accessed or updated separately from the main entity.
To create a parameterized query, you use placeholders in the SQL statement, often denoted by ________.
- dollar signs
- exclamation marks
- percent signs
- question marks
In parameterized queries, placeholders are typically denoted by question marks (?). These question marks serve as positional markers for where the input data should be inserted into the SQL statement. When executing the query, the actual values are bound to these placeholders, ensuring proper sanitation and preventing SQL injection attacks.
The ___________ property of a data-bound control specifies the source of data for binding.
- DataBinding
- DataBindingSource
- DataControlSource
- DataSource
The DataSource property of a data-bound control specifies the source of data for binding, allowing the control to display data retrieved from the specified data source.
Which LINQ operator is used to filter elements in a sequence based on a specified condition?
- GroupBy
- OrderBy
- Select
- Where
The Where operator is used to filter elements in a sequence based on a specified condition. It takes a predicate as an argument and returns a new sequence containing only the elements that satisfy the specified condition. This is commonly used for filtering data in LINQ queries.
What does EDM stand for in the context of ADO.NET?
- Entity Data Model
- Extended Data Model
- Entity Definition Model
- Entity Descriptor Model
The correct option is Entity Data Model. EDM (Entity Data Model) is an abstract conceptual representation of the data in a database. It provides a consistent and uniform way to access and manipulate data across various data sources.
What is the difference between a dataset and a data reader in ADO.NET?
- Dataset can only hold a single result set while a data reader can hold multiple result sets
- Dataset is forward-only and read-only while a data reader is updateable
- Dataset is optimized for performance while a data reader is optimized for memory usage
- Dataset provides disconnected access to data while a data reader provides connected access
The primary difference between a dataset and a data reader in ADO.NET is that a dataset provides disconnected access to data, meaning it retrieves and stores data in memory independently of the data source. On the other hand, a data reader provides connected access to data, requiring an active connection to the data source while reading data sequentially. This fundamental distinction impacts factors such as performance, memory usage, and flexibility in data manipulation.
Scenario: Your application needs to allow users to edit data within the displayed table. Which property or feature would you enable in the chosen control?
- AllowEdit property
- EditMode property
- Editable property
- EditingEnabled property
To enable users to edit data within the displayed table, you would set the EditingEnabled property to true in the chosen control, such as DataGridView. This property allows users to modify cell values directly within the grid, providing a seamless editing experience. By enabling editing functionality, users can make changes to the data without the need for additional forms or dialogs, enhancing the usability of the application.
In ADO.NET, what is the role of the DataRow object when modifying data?
- Represents a single table of data
- Represents a single row of data
- Represents a dataset
- Represents a database connection
The correct option is Represents a single row of data. DataRow object in ADO.NET represents a single row of data within a DataTable. It allows modification, addition, and deletion of data in the DataTable. The other options do not accurately describe the role of a DataRow object.