ado net books

(This post is posted on the old blog of the version engineer on)Sometimes, according to the project requirements, we may need to obtain multiple sets of datatables from the database, and thenLineCompile the code and present it on the ASP. NET 2.0 page in the desired format, instead of directly binding it to the gridview control. You can refer to the following practices.To join data from multiple tables in the database, multiple records (quantity is no

connection is established, close is not closed directly, but is saved in the connection pool.on the next connection, if the connection string is the same, the connection in the connection pool is called. instead of re-establishing. This will improve some efficiency. This has been verified in the experiment one .1. The Conn object is destroyed, and the connection in the connection pool is not destroyed.2. Connection pooling is provided by ADO, not t

We need to constantly read and write the database, so ExecuteNonQuery (), ExecuteReader () and ExecuteScalar () are what we need to use in database operations. Let's take a look at them one by one:ExecuteNonQuery (): This item allows us to use ExecuteNonQuery to change data in the database without using DataSet when updating the database. You can modify data in the database by executing UPDATE, INSERT, or delete SQL statements. Even if ExecuteNonQuery does not return any rows, the output paramet

treated as a staging area (Cache), which preserves the data queried from the database and even displays the entire database. The ability of a dataset is not just to store multiple tables, but also to get some data table structures, such as primary keys, through DataSetCommand objects, and to record correlations between data tables. The DataSet object can be said to be a heavyweight object in ADO, which is not inherently capable of communicating with

Methods and Techniques for using ADO. NET The following code illustrates how to use the SqlDataAdapter object to generate a DataSet or able command. It retrieves a group of product categories from the SQL Server Northwind database. Using System. Data; Using System. Data. SqlClient; Public DataTable RetrieveRowsWithDataTable () { Using (SqlConnection conn = new SqlConnection (connectionString )) { Conn. Open

Ado. net Connect to SQL ServerThe SQL Server. NET Framework Data Provider supports connection string formats similar to OLE DB (ADO) connection string formats.Using (sqlconnection connection = new sqlconnection (connectionstring )){Connection. open ();// Do work here.} Connect to the ole db data source (ACCESS)Ole db.

Survival Confirmation! We come to the battlefield of the database, here, if you do not master the combat skills, may not even a day to live. So let's start with the most basic ADO in the. NET Framework. With this in hand, you can barely survive the battlefield of this database.Ado. NET is divided into five major categories , there are two ways to manipulate the

When you generate an ADO. NET Entity Data Model (Entity Data Model) through a database, the number of entity classes generated may be less than the number of data tables. The following describes two possible causes. 1. All columns of the data table can be empty. When a data table has a primary key, the object data model uses the primary key as the entity key to identify an object. If the data table does n

Database Operations mainly involve executing commands and reading data. 1. Connection To access the database, you must first establish a connection with the database. In ADO. net, the connection object is used to establish a connection with the database. For example, the code used to establish a connection to the mycharge database on the sqlserver Server: Dim cnstr as string = "Password = 123456; persi

Today I reviewed the ADO and summed up their knowledge.ADO is a set of classes that expose data access services to. NET programmers. Provides access to a variety of relational data, XML, and application data.All data access classes are located in System.Data.dll. The System.Data contains a dataset and other support classes, and the System.Data.SqlClient data provider is dedicated to the SQL Server database.

will usually be: Traverse query full table data, then filter at OO level Needlessly perform instantiation, query, or waste cache resources, or waste query resources I can only say that this is a developer level issue, although it is difficult to locate after a problem, especially in general, will cause memory leaks.Finally, the most common is back to the data model synchronization problem. When the data model changes, it needs to be synchronized, and if there is already busine

ado| data ADO. Analysis of most table operations in net-read Author: Zhengzo??????? 2004-8-5 ???????? In the development based. NET Platform database application, we generally use dataset, as the core class of Ado.net it provides us with powerful functions, and the whole looks like a small database in memory, includi

ADO. NET generic database category, general database ado.net The examples in this article share the ADO. NET generic database category for your reference. The details are as follows: Using System; using System. collections. generic; using System. linq; using System. text; using System. threading. tasks; using System. d

ADO. NET1.vb.net:Vb.net does not support database operations. NET Framwork SDK for database programming class libraries and Microsoft MDAC implementation, where ADO. NET is. NET Framwork SDK is an important part. It is a general term for class libraries used to operate Numer

Ado. Net-Important classes Some experience with. NET access to MySQL database!stringConnstr=setting.instance (). GetConnectionString ("MYSQL"); Mysqlconnection Conn=Newmysqlconnection (CONNSTR); Conn. Open ();stringquery ="INSERT INTO Myfirst (id,name) VALUES (? Id? Name)"; Mysqlcommand cmd=NewMysqlcommand (query, conn); Mysqlparameter para1=NewMysqlparameter (

I recently used the ado.net Data model to connect to Oracle. I have been directly using OleDbConnection in the System. Data namespace to directly execute SQL statements.(Http://blog.csdn.net/yysyangyangyangshan/article/details/6999304) generally write SQL statements directly, and then call the corresponding execution method can be, return data to save with dataTable. However, in. net framework4.0, for example, OracleCommand will prompt that it is out

[Transfer] http://www.bitscn.com/pdb/dotnet/200807/147205.html If youProgramThe SQL statement or stored procedure executed in only returns the computed "single value", for example: Select count (*) from employee data table Or only the "first" column value of the "first" record meeting the condition will be returned. For example: Select email from employee data table where name = 'David' We can use the executescalar method of the command object (ADO