Introduction
The SqlDataAdapter serves as a bridge between a DataSet and SQL Server for retrieving and
saving data. 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. The update is performed on a by-row basis. For every
inserted, modified, and deleted row, the Update method determines the
type of change that has been performed on it (Insert, Update, or
Delete).
Depending on the type of change, the Insert, Update, or
Delete
command template executes to propagate the modified row to the data source.
When the SqlDataAdapter fills a DataSet, it creates the necessary
tables and columns for the returned data if they do not already exist. However,
primary key information is not included in the implicitly created schema unless
the MissingSchemaAction property is set to AddWithKey. You may
also have the SqlDataAdapter create the schema of the DataSet, including
primary key information, before filling it with data using FillSchema.
For more information, see Adding Existing Constraints to a DataSet (ADO.NET).
SqlDataAdapter is used in conjunction with SqlConnection
and SqlCommand to increase performance when connecting to a SQL Server
database.
The
SqlDataAdapter also includes the SelectCommand, InsertCommand,
DeleteCommand,
UpdateCommand, and TableMappings properties to facilitate the
loading and updating of data.
When an
instance of SqlDataAdapter is created, the read/write properties are set
to initial values. For a list of these values, see the SqlDataAdapter
constructor.
The InsertCommand,
DeleteCommand, and UpdateCommand are generic templates that are
automatically filled with individual values from every modified row through the
parameters mechanism.
Step 1
First Overload
DataAdapter.Fill
(ds) here fetches the data from User and fills in the DataSet ds.
Output
Step 2
Second Overload
Here DataAdapter.Fill
(dt) fetches records from Users and fills in the DataTable named
dt.
Output
Step 3
Third Overload
Here a
datatable named User has been filled by the DataAdapter.Fill () method.
Output
Step 4
Fourth Overload
This overload takes three parameters. The types of parameters are int,
int, and DataTable. Here first parameter is the starting record, second parameter is the
maximum number of record and the last parameter is the DataTable where we have to fill the records. The ranges from which the records are to be fetched are
mentioned here using the parameters.
Output
Step 5
Fifth Overload
At last,
this overload takes four parameters. The types of parameters are DataTable,
int,
int,
string. The first parameter is the name of the dataset, second parameter is the
starting record number, third parameter is the maximum number of records and
the last parameter is the name of the table.
At first ds
is filled with all the records of Users. And then, DataAdapter.Fill ()
method has filled the DataTable nm with the specified range of records.
Output
