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.
What is LINQ an abbreviation for in the context of programming?
- Language Integrated Query
- Lightweight Interface Query
- Limited Integration Query
- Linked Interaction Query
LINQ stands for Language Integrated Query. It is a feature of .NET that provides a unified way of querying data from different data sources using a SQL-like syntax directly within C# or VB.NET code. It allows developers to write queries against collections, databases, XML, and other data sources.
What is the key difference between executing a SELECT command and executing a DELETE command in ADO.NET?
- DELETE command removes data
- DELETE command updates data
- SELECT command manipulates data
- SELECT command retrieves data
In ADO.NET, a SELECT command is used to retrieve data from a database table based on specified criteria, whereas a DELETE command is used to remove data from a table based on certain conditions. Therefore, the key difference lies in their actions: SELECT retrieves data, while DELETE removes data from the table. Understanding this fundamental distinction is crucial in database manipulation using ADO.NET.
How does ADO.NET handle resource management for connections that are not explicitly closed by the application?
- Automatic garbage collection
- Connection pooling
- Finalization process
- Timeout mechanism
ADO.NET handles resource management for connections that are not explicitly closed by the application by employing connection pooling. When a connection is not explicitly closed, it is returned to the connection pool instead of being immediately disposed of. This allows the connection to be reused by subsequent requests, improving performance and resource utilization.