What is the SqlDataReader used for?
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.
What is difference between SqlDataReader and SQlDataAdapter?
A SqlDataAdapter is typically used to fill a DataSet or DataTable and so you will have access to the data after your connection has been closed (disconnected access). The SqlDataReader is a fast forward-only and connected cursor which tends to be generally quicker than filling a DataSet/DataTable.
What does SqlDataReader return?
As explained earlier, the SqlDataReader returns data via a sequential stream. To read this data, you must pull data from a table row-by-row Once a row has been read, the previous row is no longer available.
What is DataSet and DataReader?
The DataSet class in ADO.Net operates in an entirely disconnected nature, while DataReader is a connection oriented service. DataSet is an in-memory representation of a collection of Database objects including related tables, constraints, and relationships among the tables.
What is SqlDataReader in asp net?
DataReader Object in ADO.NET is a stream-based , forward-only, read-only retrieval of query results from the Data Sources , which do not update the data. The DataReader cannot be created directly from code, they can created only by calling the ExecuteReader method of a Command Object.
What is SqlDataReader in VB net?
SqlDataReader Object provides a connection oriented data access to the SQL Server data Sources. ExecuteReader() in the SqlCommand Object send the SQL statements to SqlConnection Object and populate a SqlDataReader Object based on the SQL statement.
Is SqlDataReader faster than SQlDataAdapter?
SqlDataReader will be faster than SQlDataAdapter because it works in a connected state which means the first result is returned from query as soon as its available ..
What is SQlDataAdapter and DataSet?
The SqlDataAdapter 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, using the appropriate Transact-SQL statements against the data source.
Why do we use SQlDataAdapter?
SqlDataAdapter is used in conjunction with SqlConnection and SqlCommand to increase performance when connecting to a SQL Server database. If you are using SQL Server stored procedures to edit or delete data using a DataAdapter , make sure that you do not use SET NOCOUNT ON in the stored procedure definition.
What is the difference between ExecuteScalar and ExecuteReader?
ExecuteScalar is typically used when your query returns a single value. If it returns more, then the result is the first column of the first row. An example might be SELECT @@IDENTITY AS ‘Identity’ . ExecuteReader is used for any result set with multiple rows/columns (e.g., SELECT col1, col2 from sometable ).
What is difference between ExecuteScalar and ExecuteNonQuery?
Solution 1. ExecuteScalar() only returns the value from the first column of the first row of your query. ExecuteReader() returns an object that can iterate over the entire result set. ExecuteNonQuery() does not return data at all: only the number of rows affected by an insert, update, or delete.