The example above uses a string indexer, where the string is the column name from the sql query the table column name if you used an asterisk. Dataadapter is a class that represents a set of sql commands and a database connection. I want to fill a dataset with 20,0000 records using a sqldataadapter by using this code. The dataadapter works as a bridge between a dataset and a data source to retrieve data. Sqldataadapter contains all necessary commands, and the example above reveals only a select operation. We can use sqldataadapter object in combination with dataset object. Net dataadapter is the link between a database connection and a dataset or a datareader.
It uses fill method to retrieve data from data source and fill it in dataset. The fill method of the dataadapter is used to populate a dataset with the results of the selectcommand of the dataadapter. Introduction the sqldataadapter serves as a bridge between a dataset and sql server for retrieving and saving data. Here is an example of an update command for a dataadapter that uses a stored procedure. In the example functions below im illustrating how to set up a basic query to a stored procedure in your database that takes a single string parameter. You will need to change the select command to use a table from your custom database. The sqlcommand type has a public parameterized constructor and it can be used with one or more arguments. Database i have made use of the following table customers with the schema as follows. Auffullen eines datasets mit mehreren dataadapterobjekten. Sqldataadapter provides the communication between the dataset and the sql database. The sqldataadapter provides this bridge by using system. The following example creates a sqldataadapter and sets some of its properties public static sqldataadapter createsqldataadaptersqlcommand selectcommand, sqlconnection connection sqldataadapter adapter new sqldataadapter selectcommand. This article has been excerpted from book a programmers guide to ado. The dataset represents a complete set of data that includes tables, constraints, and relationships among the tables.
In many applications, this means reading data from a database into a dataset, and then writing changed data from the dataset back to the database. I tried commenting but was told to reread the question. We use sqlcommand in the context of a complete but trivial program that reads data from a specific database on the disk. The sqlconnection object has no information about the data it retrieves. Stored procedures that return both output parameters and. You can extract each column of the row with a numeric indexer like this, but it isnt very readable. However, a data adapter can move data between any source and a dataset. Stored procedures that return both output parameters and table results. Two ways exist for adding insert, update, and delete commands. The following example creates a mysqlcommand and a mysqlconnection. Fill takes as its arguments a dataset to be populated, and a datatable object, or the name of the datatable to be filled with the rows returned from the selectcommand. The sqldataadapter serves as a bridge between a system. The mysqlconnection is opened and set as the connection for the mysqlcommand.
What to choose between sqldataadapter, executescalar and executenonquery by christos s. Selectcommand maintains a reference to the previously created sqlcommand object. Selectcommand is assigned to a previously created sqlcommand, the sqlcommand is not cloned. A look into the five different overloads of the dataadapter. Use sqldataadapter with sql to populate a datatable for use in windows forms. Similarly a dataset has no knowledge of the data source where the data coming from. First, create a windows application using visual basic projects and add two buttons and a datagrid control to the form by dragging the controls form the toolbox to the form.
Net code samples to demonstrate how the sqldataadapter object can be used to update a sql server database with data modifications executed on a dataset object that is populated with data from a table in the database. Correct is d, you pass an empty dataset into the dataadapter which uses the selectcommand to fill it. To accomplish this, the executenonquery is passed a connection string and a query string that is a sql insert statement. Fill to load data from the data source into the system. Dataadapter with dataset sql sever sqldataadapter provides the communication between the dataset and the data source with the help of sqlconnection object. Now youll create your first sample using data adapters. Auffullen eines datasets durch einen dataadapter ado. Selectcommand does not return any rows, no tables are added to the system. Open connection using sqlconnection c new sqlconnection properties. You have very little code in that example which ties dt you say this is. In this sample example, ill show you how to create data adapters using sql and oledb data providers and fill data from data from data adapter to a datagrid control. The following code example creates an instance of a sqldataadapter that uses a sqlconnection to the microsoft sql server northwind database and populates a datatable in a dataset with the list of customers.
Net example populating a dataset using sqldataadapter. Dataadapter is used to retrieve data from a data source and populate tables within a dataset. Sep 20, 2012 a look into the five different overloads of the dataadapter. Where with datareader we can not use it because it will close the connection if we want to return the datareader back to some method.
C is rubbish because you cant use a dataset to fill a dataadapter. Net dataset is a memoryresident representation of data that provides a consistent relational programming model independent of the data source. Download trial sample pdf converter project that demonstrate the use of the export to pdf class and show the results of using the class in several. What is sqldataadapter sqldataadapter is a part of the ado. The examples involve using the sqldataadapter object to fill a dataset. You can rate examples to help us improve the quality of examples.
For example, there could be an adapter that moves data between a microsoft exchange server and a dataset. Using sqldatareader and sqldataadapter codeproject. Dataset and a data source for retrieving and saving data. Find answers to dataadapter not filling datatable from the expert community at experts exchange. The useability and the interaction for the end users with your web form will reflect the term of the success and the completeness for your work,and especially if most of your web forms get and show data from database. Sqldataadapter daproducts new sqldataadapter select productid, organizationname from products, conn. The example then calls executenonquery, and closes the connection. The updatecommand of the sqldataadapter object update the database with the data modifications made on a dataset object.
Net dataadapter dataadapter serves as a bridge between a dataset and sql server for retrieving and saving data. Ausgabe einer tabelle mit hilfe eines datasetobjekts itvisions. Fill a dataset with nearly 20,0000 records using sqldataadapter. Dataadapter not filling datatable solutions experts exchange. Net datareader to retrieve a readonly, forwardonly stream of data from a database. Results are returned as the query executes, and are stored in the network buffer on the client until you request them using the read method of the datareader. A adds a new row, b doesnt have a select command defined. So do you think the following technique is fine with datareader and the using keyword. It can be used to fill the dataset and update the data source. String indexers are much more readable, making the code easier to maintain.
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