Which is the correct way to declare a DataReader?
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Which is the correct way to declare a DataReader?
After creating an instance of the Command object, you create a DataReader by calling Command. ExecuteReader to retrieve rows from a data source, as shown in the following example. SqlDataReader myReader = myCommand. ExecuteReader();…ADO.NET DataReader
- SqlDataReader.
- OleDbDataReader.
- OdbcDataReader.
What is the use of DataReader?
The DataReader provides an unbuffered stream of data that allows procedural logic to efficiently process results from a data source sequentially. The DataReader is a good choice when you’re retrieving large amounts of data because the data is not cached in memory.
Which method is used by DataReader in VB net?
The Read() method in the DataReader is used to read the rows from DataReader and it always moves forward to a new valid row, if any row exist . There are two types of DataReader in ADO.NET. They are SqlDataReader and the OleDbDataReader.
Which method is used by DataReader in VB NET?
What is the difference between DataAdapter and DataReader?
DataAdapter is like a mediator between DataSet (or) DataTable and database. This dataadapter is used to read the data from database and bind to dataset. DataReader is used to read the data from database and it is a read and forward only connection oriented architecture during fetch the data from database.
What are the features of DataReader?
SqlDataReader Properties
| Property | Description |
|---|---|
| Depth | It is used to get a value that indicates the depth of nesting for the current row. |
| FieldCount | It is used to get the number of columns in the current row. |
| HasRows | It is used to get a value that indicates whether the SqlDataReader contains one or more rows. |
What is the difference between DataReader and DataSet in VB net?
1. DataReader is used to retrieve read-only (cannot update/manipulate data back to datasource) and forward-only (cannot read backward/random) data from a database. It provides the ability to expose the data from database while DataSet is a collection of in-memory tables. wait for the entire query to execute.
What is DataAdapter and DataReader?
Using the DataReader can increase application performance both by retrieving data as soon as it is available, and (by default) storing only one row at a time in memory, reducing system overhead. A DataAdapter is used to retrieve data from a data source and populate tables within a DataSet.
How many DataTables are in a DataSet?
So 2^32 is the maximum number of DataTables you can hold inside a DataSet (2,147,483,648 tables, happy coding). By the way, a DataTable can contain 16,777,216 rows, but that’s not what you’ve asked. Show activity on this post. The maximum size is limited by Int32 is 2^32, since Tables.
What is DataAdapter in VB net?
The DataAdapter serves as a bridge between a DataSet and a data source for retrieving and saving data. The DataAdapter provides this bridge by mapping Fill, which changes the data in the DataSet to match the data in the data source, and Update, which changes the data in the data source to match the data in the DataSet.
