ODBC, OLE DB, ADO, and ASP Questions and Answers

Answer: A

Correct answer: True

A rowset is OLE DB’s abstraction of a set of rows returned from a data source, and it plays the same role that a cursor plays in SQL - a position within a set of rows that can be moved and read through. The name changes because OLE DB generalises the idea beyond relational sources.

Answer: D

Correct answer: Both 1 and 3 above are in the OBDC core API.

The core API covers the basics every driver must provide: connecting to and disconnecting from data sources, preparing and executing SQL, retrieving results, and committing or rolling back transactions. Connecting with driver-specific information belongs to Level 1, and browsing available connections and scrollable cursors to Level 2.

Answer: B

Correct answer: Connect to data sources with driver-specific information only

Level 1 adds to the core the ability to connect using driver-specific connection information, to send and receive partial results, and to retrieve catalogue information and details of the driver’s own capabilities. Browsing possible connections and processing a scrollable cursor are Level 2 functions, one conformance level higher.

Answer: B

Correct answer: False

It is the other way round. A file data source keeps its connection details in a file that can be placed on a share and used by many people; it is the system data source that is local to a single computer, and the user data source that is narrower still, being local to one user on one computer.

Answer: B

Correct answer: False

ODBC is deliberately not Microsoft-specific: it is an industry interface, implemented on many platforms and by many DBMS vendors, which is what makes DBMS-independent application code possible. It is OLE DB that is the foundation of data access in the specifically Microsoft world, being built on COM.

Answer: A

Correct answer: True

Conformance is graded in two independent dimensions: the API conformance level, which says which function calls the driver supports, and the SQL grammar conformance level, which says which statements, expressions and data types it can process. An application can therefore check that a driver is capable of what it intends before relying on it.

Answer: A

Correct answer: True

That is what makes a provider tabular: it owns data and exposes it as rowsets, the OLE DB abstraction of a set of rows. A service provider is the other kind, owning no data and instead transforming what it consumes from a provider below before exposing it again.

Answer: D

Correct answer: All of the above are true of an OLE DB service provider.

A service provider owns no data of its own. It sits between a consumer and a data provider, taking data in through an OLE DB interface, transforming it - sorting, querying, converting - and exposing the result through another. Being fed by one interface and exposing another makes it simultaneously a consumer and a provider, which is exactly what allows providers to be chained.

Answer: B

Correct answer: False

The order is the other way round. The connection object is created first, and the errors collection belongs to it - errors arising from operations on that connection are placed there. A collection cannot exist before the object that contains it, so the errors object follows the connection rather than preceding it.

Answer: A

Correct answer: INSERT, UPDATE, DELETE only

The minimum grammar is the smallest set a driver must support to be ODBC compliant: the data manipulation statements, simple CREATE TABLE and DROP TABLE, a simple SELECT, and the basic expressions. Views and stored procedures belong to the core and extended grammars respectively, which is how the three conformance levels are graded.