You looked detail the datareader and dataset objects
186 CHAPTER 5 ■ DATAREADER AND DATASET
Table 5-3. Characteristics of DataReaders and DataSets
| DataReader |
|---|
A DataReader presents data through a direct connection to the data source.
Only one row of data is stored in memory at any one time.
You can’t update a data source through a DataReader.
A DataReader connects to only one data source.
A DataSet takes up a lot more IIS and memory
resources to store all the data, but it doesn’t hold up a database connection until it’s closed. The connection needs to be open only when Fill() is called.A DataSet lasts only until the page is reloaded (posted back), unless it’s somehow persisted (for example, in a session variable).
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Good Practices
• If you’re using a DataSet, be aware of how calling Fill() will work with the DataSet you’re using. Will it create new columns in a DataTable or use the other ones there? Make sure the columns you’re querying for in the database match those in the DataTable you’re targeting.
• Don’t forget that primary keys and relationships in a DataSet won’t be copied over from a database. You must create them in code.
In the next chapter, you’ll begin your exploration of data binding, beginning with inline and list binding.
