Tutorial by Examples: connection

UCanAccess is a pure Java JDBC driver that allows us to read from and write to Access databases without using ODBC. It uses two other packages, Jackcess and HSQLDB, to perform these tasks. Once it has been set up*, we can work with data in .accdb and .mdb files using code like this: import java.sq...

Another use of RODBC is in connecting with SQL Server Management Database. We need to specify the 'Driver' i.e. SQL Server here, the database name "Atilla" and then use the sqlQuery to extract either the full table or a fraction of it. library(RODBC) cn <- odbcDriverConnect(connect...

The first step in accessing a data source via ADO is creating an ADO Connection object. This is typically done using a connection string to specify the data source parameters, although it is also possible to open a DSN connection by passing the DSN, user ID, and password to the .Open method. Note t...

Driver: 12c R1 11g R2 (Note: the driver is not included in Maven Central!) Driver class initialization: Class.forName("oracle.jdbc.driver.OracleDriver"); Connection URL Older format, with SID "jdbc:oracle:thin:@<hostname>:<port>:<SID>" Newer...

To check that the connection to the server is valid: sqoop list-tables --connect "jdbc:sqlserver://<server_ip>:1433;database=<database_name>" --username <user_name> --password <password> Before doing this it is recommended ...

DatabaseTransactions trait allows databases to rollback all the change during the tests. If you want to rollback multiple databases , you need to set $connectionsToTransact properties use Illuminate\Foundation\Testing\DatabaseMigrations; class ExampleTest extends TestCase { use Databas...

Quite often it's necessary to send/upload a file to a remote server, for example, an image, video, audio or a backup of the application database to a remote private server. Assuming the server is expecting a POST request with the content, here's a simple example of how to complete this task in Andro...

$dbServer = "localhost,1234"; //Name of the server/instance, including optional port number (default is 1433) $dbName = "db001"; //Name of the database $dbUser = "user"; //Name of the user $dbPassword = "password"; //DB Password of that user $connectionI...

public class ConnectSocketExample { private int HTTP_PORT = 80; /** * example method to create unconnected socket * then connect to it * at end return connected socket * * @param httpHostName - endpoint host name fot socket connection * @throws IOEx...

The using keyword ensures that the resource defined within the statement only exists within the scope of the statement itself. Any resources defined within the statement must implement the IDisposable interface. These are incredibly important when dealing with any connections that implement the IDi...

Vital to using character sets is to tell the MySQL-server what encoding the client's bytes are. Here is one way: SET NAMES utf8mb4; Each language (PHP, Python, Java, ...) has its own way the it usually preferable to SET NAMES. For example: SET NAMES utf8mb4, together with a column declared CH...

A transaction acts on a single database connection. If you have multiple class-specific databases, the transaction will not protect interaction among them. One workaround is to begin a transaction on each class whose models you alter: Student.transaction do Course.transaction do course.enro...

ADO.NET Connections are one of the simplest ways to connect to a database from a C# application. They rely on the use of a provider and a connection string that points to your database to perform queries against. Common Data Provider Classes Many of the following are classes that are commonly used...

Entity Framework exposes abstraction classes that are used to interact with underlying databases in the form of classes like DbContext. These contexts generally consist of DbSet<T> properties that expose the available collections that can be queried : public class ExampleContext: DbContext ...

A Connection String is a string that specifies information about a particular data source and how to go about connecting to it by storing credentials, locations, and other information. Server=myServerAddress;Database=myDataBase;User Id=myUsername;Password=myPassword; Storing Your Connection Stri...

Connection factories are the managed objects that allows application to connect to provider by creating Connection object. javax.jms.ConnectionFactory is an interface that encapsulates configuration parameters defined by an administrator. For using ConnectionFactory client must execute JNDI lookup ...

Set up some constants for the server and authentication information. Assuming LDAPv3, but it's easy enough to change that. // Authentication, and the name of the server. private const string LDAPUser = "cn=example:app:mygroup:accts,ou=Applications,dc=example,dc=com"; private readonly ch...

A "Connection Refused" error will occur if your client sends a connection request to a remote server host, and the remote host responds to say that it refuses to accept the request. The "Connection Refused" error essentially means that the computer is not accepting connections to...

A "Connection timed out" error occurs when the remote system does not respond to the client's attempt to open a TCP/IP connection. The most common causes include: A firewall is blocking the connection attempt on the port that you are using: The firewall could be on the client-side, ...

The following class can be used as a single class that can handle GET, POST, PUT, PATCH, and other requests: class APIResponseObject{ int responseCode; String response; APIResponseObject(int responseCode,String response) { this.responseCode = responseCode; ...