Which method is used to advance the data reader to the next record in the result set?
- Advance()
- MoveNext()
- NextRecord()
- ReadNext()
The MoveNext() method is used to advance the data reader to the next record in the result set. This method moves the cursor to the next row, allowing access to the data in that row. It is essential for iterating through the result set and processing each record sequentially.
You have a complex inheritance hierarchy in your entity model. How can Entity Framework help you map these entities to the appropriate database tables?
- Entity Splitting
- Table-per-Concrete-Type (TPC)
- Table-per-Hierarchy (TPH)
- Table-per-Type (TPT)
Entity Framework provides support for mapping complex inheritance hierarchies to database tables using Table-per-Hierarchy (TPH) strategy. In TPH mapping, all classes in the inheritance hierarchy are mapped to a single database table, with a discriminator column used to differentiate between different types of entities. This approach simplifies the database schema by reducing the number of tables required to represent the inheritance hierarchy, making it easier to manage and query related entities.
To navigate through hierarchical data, you can use the ___________ property of a DataRow.
- ChildRows
- GetChildRows()
- GetParentRow()
- ParentRow
The ChildRows property of a DataRow allows you to access all the child rows related to the current DataRow through the specified DataRelation. This is particularly useful when working with hierarchical data structures in ADO.NET.
In a SELECT statement, what keyword is used to specify which columns to retrieve from a table?
- FROM
- INTO
- SELECT
- WHERE
In a SELECT statement, the "SELECT" keyword is used to specify which columns to retrieve from a table. It is followed by the column names or expressions that you want to retrieve data from.
When should you use parameterized queries instead of plain SQL statements?
- When dealing with static data retrieval
- When executing complex joins
- When handling database schema modifications
- When performing queries involving user input
Parameterized queries should be used when performing queries involving user input to prevent SQL injection attacks. By using parameterized queries, input values are treated as data rather than executable code, making it much harder for attackers to inject malicious SQL code into the query. This helps enhance security and protect the database from unauthorized access.
The _________ property of a SqlParameter determines whether a parameter is an input or output parameter.
- Direction
- Name
- Type
- Value
In ADO.NET, the Direction property of a SqlParameter object determines whether the parameter is an input parameter, an output parameter, or both. This property is crucial for specifying the role of the parameter in the stored procedure.
When using a JOIN clause in a SELECT statement, you are typically combining data from ___________ tables.
- Related
- Associated
- Connected
- Linked
The correct option is Option 4: Linked. In SQL, a JOIN clause is used to combine rows from two or more tables based on a related column between them. It links the tables together to create a single, unified dataset for analysis or manipulation.
How can you handle data conflicts when multiple users are trying to modify the same data in a dataset simultaneously?
- Ignore conflicts
- Lock the dataset
- Use optimistic concurrency control
- Use pessimistic concurrency control
Handling data conflicts in ADO.NET involves implementing optimistic concurrency control, where the system assumes that conflicts are rare. When multiple users attempt to modify the same data concurrently, the system checks if the data has been altered since it was retrieved. If the data has changed, it prevents the modification and notifies the user, allowing them to resolve the conflict.
Scenario: You have a DataTable containing sales data for a year. You need to create a DataView that displays only the sales records for a specific region. Which property of the DataView would you use to achieve this?
- AllowNew
- RowFilter
- RowStateFilter
- Sort
The correct option is "RowFilter". This property allows you to specify a filter expression to restrict which rows are viewed in the DataView. By setting the RowFilter property to a condition that filters records based on the specific region, you can achieve the desired outcome.
When working with LINQ to Entities, what is an ObjectContext?
- A class representing a connection to the database
- A data structure for storing entity objects
- An attribute for defining relationships
- An interface for querying databases
An ObjectContext in LINQ to Entities represents a connection to the database. It holds metadata about the entities and maintains state information. It is responsible for tracking changes and managing connections and transactions. This is crucial for managing interactions with the underlying database in an Entity Framework application.