使用数据集的Load方法或DataAdapter的Fill方法之间的区别

Question

Can anyone tell me difference in two below methods of geting records from SQL DB ?

Declarations

Dim Cmd As New OdbcCommand
Dim OdbcDr As OdbcDataReader
Dim OdbcAd As OdbcDataAdapter

---

Method one : Using OdbcDataReader and Loading data in Data Table

OdbcDr = Cmd.ExecuteReader()
dt.Load(OdbcDr)
Return dt

Method two: Using OdbcDataAdapter and filling data in Data Table

OdbcAd = New OdbcDataAdapter(Cmd)
OdbcAd.Fill(dt)
Return dt

Which method I should use ?

Answer 1

A DataReader is exactly what it sounds like, all it does is read from the source and allows you to do whatever with the results. In contrast, a DataAdapter is a two-way bridge between you and the data. You can use the Fill() method to retrieve data from your connection but it also works the other way around, where you can use the Update() method to pass changes from your DataSet/DataTable into your database.

AFAIK there's no real reason to use a DataAdapter where a DataReader will do, it should be faster.

Here's some literature about it.