A file data source is one that is local to a single computer.
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.
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An application that uses the ODBC interface could process any database that is ODBC-compliant without any program coding changes.
Answer: A
Correct answer: True
This is the whole purpose of the interface. The application issues standard ODBC calls and names a data source; the driver manager loads the appropriate driver, and the driver translates those calls for the particular DBMS. Point the data source at a different compliant database and the application works against it unchanged.
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An OLE DB rowset is equivalent to a cursor.
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.
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ODBC is a foundation of data access in the specifically Microsoft world.
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.
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An abstraction is a generalization of something.
Answer: A
Correct answer: True
An abstraction is a generalisation that captures what a group of things have in common while suppressing their differences. The idea runs right through OLE DB: a rowset is an abstraction of rows however they are actually stored, which is what allows one interface to serve a relational database, a spreadsheet and a mail store alike.
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An OLE DB interface is specified by a set of objects and the properties and methods that they expose.
Answer: A
Correct answer: True
This is the definition of an interface in the object model: the set of objects it exposes together with the properties and methods those objects make available. A provider implements the interfaces it can support and no others, and a consumer discovers what is available and uses that - which is what gives OLE DB its flexibility.
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A OLE DB rowset is an abstraction of a relation, which in turn is an abstraction of a recordset.
Answer: B
Correct answer: False
The nesting is the wrong way round, and one term is redundant. A rowset is the OLE DB abstraction, generalising the recordset or relation to any kind of data source. A relation is not an abstraction of a recordset; the two are near synonyms at the same level, and the rowset is the generalisation of both.
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ODBC identifies two types of drivers: single tier and multiple-tier.
Answer: B
Correct answer: True
ODBC does identify exactly these two kinds. A single-tier driver processes both the ODBC calls and the file access itself, which is how a driver for a simple file format such as a spreadsheet works. A multiple-tier driver passes SQL to a separate DBMS, which does the processing, and is the arrangement used for a client-server database.
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ODBC identifies two types of drivers: single tier and multiple-tier.
Answer: A
Correct answer: True
ODBC does identify exactly these two kinds. A single-tier driver processes both the ODBC calls and the file access itself, which is how a driver for a simple file format such as a spreadsheet works. A multiple-tier driver passes SQL to a separate DBMS, which does the processing, and is the arrangement used for a client-server database.
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A data source is an ODBC data structure that identifies a database and the DBMS that processes it.
Answer: A
Correct answer: True
This is the definition. The data source names both the database and the DBMS that processes it, along with the other details needed to reach it, and the application connects to it by name. The indirection is deliberate: what the name refers to can be changed without touching the application.
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