ADO.Net Interview Question on DataSet

ADO.Net Interview Question on DataSet page 1

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1. What is DataSet?
DataSet is an in-memory cache of data retrieved from data source; it consists of collection of DataTable objects.
2. In which namespace DataSet is available?
System.Data
3. Can we add more than one table to DataSet?
Yes
4. Can you relate and enforce constraints on tables in DataSet?
Yes, we can relate tables in DataSet with DataRelation objects and we can enforce UniqueConstraint and ForeignKeyConstraint objects.
5. How can you clear data from all the tables in a DataSet?
DataSet.Clear() method clears the data from all tables in DataSet
6. Can I read xml document that includes both schema and data into DataSet?
Yes, ReadXml() is used to read xml document that includes both schema and data.
7. What is the difference between DataSet.Copy() and DataSet.Clone()?
DataSet.Clone() :- Copies the structure of the DataSet, i.e schema of all data tables, relations and constraints. It does not copy any data. DataSet.Copy() :- Copies both the structure and data of the DataSet.
8. How can you save all edits/changes of data in DataSet to DataBase?
By using DataSet AcceptChanges() method, we can update database
9. What happens when you invoke Dataset’s AcceptChanges() method?
By invoking AcceptChanges on the DataSet causes AcceptChanges to be called on each table with in DataSet. Calling AcceptChanges at the DataTable level causes the AcceptChanges method for each DataRow to be called. When you call AcceptChanges on the DataSet, any DataRow objects still in edit-mode successfully end their edits. The RowState property of each DataRow also changes; Added and Modified rows become Unchanged, and Deleted rows are removed.
10.How do you find a DataSet has any changes made to it, since it was last loaded?
DataSet.HasChanges() :- method returns true if the DataSet has changes; otherwise false.
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