Hour 19

for RuBoard

Quiz Answers


CommandBuilder will generate UPDATE and DELETE statements following which concurrency model?

  1. Pessimistic concurrency model

  2. Optimistic concurrency model

  3. Data update concurrency model


b. The optimistic concurrency model, which means that other users can update data that has been selected by your application and your application must check for this before committing your updates.


True or false: Automatically generated commands will be created for all SelectCommands coded in Visual Basic or C#.


False. You must explicitly activate this capability by using the CommandBuilder object.


What must be done following the change of a SELECT statement when using CommandBuilder to automatically generate code?

  1. Reassign SELECT variables

  2. Refresh metadata

  3. Close connection

  4. Open connection


b. Refresh metadata. This is done using the .Refreshschema() method. You would then clear out ( .Remove ) the DataSet and fill it again for further processing.


True or false: The following SELECT statement is valid for using with CommandBuilder :

 SELECT a.*, b.* FROM Customers a, Orders b WHERE a.CustomerID = b.CustomerID 

False. The SelectCommand to be used with CommandBuilder must not span multiple tables.


The SelectCommand that will be used for the CommandBuilder must:

  1. Include a SELECT Distinct clause

  2. Contain all columns in the table

  3. Return at least one primary key or unique column

  4. Contain a WHERE clause with at least one filter


c. Return at least one primary key or unique column. The UPDATE and DELETE statements must be able to locate the exact data row for update/delete to ensure integrity.

for RuBoard

Sams Teach Yourself ADO. NET in 24 Hours
Sams Teach Yourself ADO.NET in 24 Hours
ISBN: 0672323834
EAN: 2147483647
Year: 2002
Pages: 237

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