I am just learning C# through Visual Studio 2008?
I was wondering what exactly is the correlation between dabases, datasets and binding sources?
As well, what is the function of the table adapter?
At a super high level:
Database -- stores raw data
DataSet -- a .NET object that can be used to read, insert, update and delete data in a database
BindingSource -- a .NET object that can be used for Data Binding for a control. The BindingSource could point to a DataSet, in which case the control would display and edit that data
TableAdapter -- Maps data from a database table into a DataSet
There is a lot more to all of these, and understanding the way ADO.NET is architected can take a bit of time. Good luck!
A DataSet is usually used to hold a result from the database in memory, i.e. it contains a DataTable object. The DataSet and DataTable objects themselfs are independent of the database, so the result doesn't have to come from a database. The DataSet can contain several DataTables, and you can even define relations between them. It's like a mini database in memory.
A binding source is any object that can provide a list of objects with properties. A DataSet or a DataTable can do that, but it could basically be any kind of list containing objects that has properties.
A TableAdapter is used to read data from a DataReader provided by a Command object, and put the data in a DataTable object.
The dataset is a (partial) in-memory representation of a database. Tables or Views in the datatbase are represented as datatables in a dataset. The dataadapter is the link between the database and the dataset. Once the adapter has loaded the data into the dataset, the physical connection to the dataset is disposed. This is why it's called a disconnected data-model.
Related
I used to work in VB.net and used Dataset's all the time when working with ADO, but now i'm Working in C# and the Research is showing me a lot of Recordsets.
Are they the same thing?
If no what is the difference?
Datasets vs RecordSets
Essentially it is to do with how it fetches the data and allows you to intereact with it, recordsets would typically only allow you to fetch data from one table at a time (with default settings) whereas datasets can retrieve the entire set of data. there is more information at that link
Dataset is a connectionless data holder whereas RecordSet is connection oriented Data holder.Though DataSet you can refer more than 1 table at a time, but in the case of Recordset only 1 table is processed at a time. Through Dataset you can process more than 1 record,but in case of recordset recordset you have to make travesel to each record and after that you can make processing.
a direct quote backing up what i said
Difference between ADO.NET Dataset and ADO Recordset?
ADO.NET is an object-oriented set of libraries that allows you to interact with data sources.
http://www.job4india.in/interview-questions/net-interview-questions
ADO :-
1.It is a COM based library.
2.Classic ADO requires active connection with the data store.
3.Locking feature is available.
4.Data is stored in binary format.
5.XML integration is not possible.
ADO.NET :-
1.It is a CLR based library.
2.ADO.NET architecture works while the data store is disconnected.
3.Locking feature is not available.
4.Data is stored in XML.
Read More :- http://www.job4india.in/net-interview-questions/what-difference-between-ado-and-adonet
No, the DataSet class (System.Data namespace) has the same name in C#. I'm not familiar with anything called recordset in ADO.NET (whereas I am with DataSet). Could you post some examples?
I am looking for a few suggestions on how I can integrate database functionality into my WPF application for fast and efficient query processing. Are there libraries I can integrate, or does C# have this built in.
What I intend to have is several tables with less than one thousand entries each. This data is read from an XML file when the application launches and is inserted into tables. All data should reside in memory so no filesystem support is necessary.
Look at ADO.net's DataSet: http://msdn.microsoft.com/en-us/library/ss7fbaez.aspx (emphasis mine):
The ADO.NET DataSet is a memory-resident representation of data that
provides a consistent relational programming model regardless of the
source of the data it contains. A DataSet represents a complete set of
data including the tables that contain, order, and constrain the data,
as well as the relationships between the tables.
There are several ways of working with a DataSet, which can be applied
independently or in combination. You can:
Programmatically create a DataTable, DataRelation, and Constraint within a DataSet and populate the tables with data.
Populate the DataSet with tables of data from an existing relational data source using a DataAdapter.
Load and persist the DataSet contents using XML. For more information, see Using XML in a DataSet (ADO.NET).
See http://msdn.microsoft.com/en-us/library/fx29c3yd.aspx for specifics on "Loading a DataSet from XML".
This is available by default in ADO.Net - one of the base .Net libraries, so it is immediately usable from C# without any additional dependencies. (Technically, C# is just a language - it doesn't provide any libraries.)
You can use ADO.NET Datasets from the xml files. Take a look here for a example
DataSet dataSet = new DataSet();
DataTable dataTable = new DataTable("table1");
dataTable.Columns.Add("col1", typeof(string));
dataSet.Tables.Add(dataTable);
string xmlData = "<XmlDS><table1><col1>Value1</col1></table1><table1> <col1>Value2</col1></table1></XmlDS>";
System.IO.StringReader xmlSR = new System.IO.StringReader(xmlData);
dataSet.ReadXml(xmlSR, XmlReadMode.IgnoreSchema);
What is dataset and datatable?
How both of them are related to each other.
And what are the uses of it.
I also want to know how to create a dataset manually and display the data in the web page using c sharp.
As i am newbie to .net and c sharp
A data set is a collection of data tables and the relationships between them. It normally represents a set of database tables and the relationships (foreign keys) between them. See DataSet on MSDN.
A data table is usually a representation of a database table, in memory. See DataTable on MSDN.
The uses are that you do not need to go to the database every time you want to lookup a value.
The rest of your question is rather broad and not really answerable, as there are many ways to create a dataset in memory. You need to be much more specific regarding what you are trying to do.
A DataSet is an in memory representation of data,It containing one or more DataTables.
A DataTable is an in-memory representation of data, typically retrieved from a database or XML source.
As far as I remember, a DataSet is a collection of DataTables and the Relations between tables.
A DataTable is an object that represents a table of data similar to a database table.
If I were you I'd avoid the use of DataSets and DataTables as they are fairly heavyweight objects and for simple display you don't need any of the extra features that they provide.
Google for information about DataReaders and maybe DataReaders vs DataTables
What is the difference between data adapter and data reader?
Please see DataReader, DataAdapter & DataSet - When to use? :
ADO.NET provides two central Data
Access Components. The excellent thing
is that, they are common across all
Databases, be it SQL Server or other
competitive databases. Its only the
namespace to be used, that differs,
while using a Database other than SQL
Server.
A DataReader is an object returned from the ExecuteReader method of a DbCommand object. It is a forward-only cursor over the rows in the each result set. Using a DataReader, you can access each column of the result set, read all rows of the set, and advance to the next result set if there are more than one.
A DataAdapter is an object that contains four DbCommand objects: one each for SELECT, INSERT, DELETE and UPDATE commands. It mediates between these commands and a DataSet though the Fill and Update methods.
Data Reader is an object used in connected Environment.
Data Adapter is an object used in Disconnected environment using Dataset.
DataReader is a faster way to retrieve the records from the DB. DataReader reads the column. DataReader demands live connection but DataAdapter needs disconnected approach.
Here is a nice article on the above topic:
Difference Between DataReader, DataSet, DataAdapter and DataTable in C#
Key differences in simple terms:
Unlike classic ADO, which was primarily designed for tightly coupled client/server systems,ADO.NET was built with the disconnected world in mind, using DataSets/DataAdapter.
DataAdapter follows connectionless-oriented architecture which simply means you need not necessarily be connected to a data-source whereas DataReader is a connection-oriented architecture which means it needs an active connection to a data-source for it to operate.
DataAdapter is an intermediate layer/ middleware which acts a bridge between the DataSet and a Database whereas DataReader provides forward-only, read-only access to data using a server-side cursor (simply put it is ued to read the data).
Using DataSet we can manipulate and update a DataSet's contents while disconnected from the Datasource and send any modified data back for processing using a related DataAdapter whereas DataReader can only read data from a Database & cannot modify it.
DataAdapter object is used to read the data from database and populates that data to DataSet whereas DataReader simply reads the data using the Read() method.
DataAdapter is comparatively slower whereas using 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.
Data reader is an object through which you can read a sequential stream of data. it's a forward only data wherein you cannot go back to read previous data.
data set and data adapter object help us to work in disconnected mode. data set is an in cache memory representation of tables. the data is filled from the data source to the data set thro' the data adapter. once the table in the dataset is modified, the changes are broadcast to the database back thro; the data adapter.
DataAdapter
DataAdapter will acts as a Bridge between DataSet and database. This dataadapter object is used to read the data from database and bind that data to dataset. Dataadapter is a disconnected oriented architecture.
DataReader
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. DataReader will fetch the data very fast when compared with dataset. Generally we will use ExecuteReader object to bind data to datareader
DataContext/Entity Model always read data from Database. is there any way DataContext/Entity Model will read the data from DataSet.
Thanks
Check out Linq-to-DataSet
LINQ to DataSet makes it easier and
faster to query over data cached in a
DataSet object. Specifically, LINQ to
DataSet simplifies querying by
enabling developers to write queries
from the programming language itself,
instead of by using a separate query
language.
There is no automated way to make LinqToSql or the EntityFramework read data from a DataSet instead of from a Database. Using a DataSet as some kind of "disconnected database" is fine for a single UnitOfWork, if you want to use it as some kind of datastore in disconnected scenarios you should consider another solution such as SQL Server CE (which you can't use with L2S but with EF).
If your scenario resembles the first one (single Unit of Work) you need to fill the data manually into the dataset and can then use Linq-To-DataSet consecutively.