How to create a database connection using SQL Developer

After SQL Develope is started, you need to create a database connection to create, change, or edit data in the schema of the database only if you have created a database connection.

The steps to create a database connection are as follows.

(1) In the Connection tab on the left window of the main interface, right-click the Connections node and select the New Connection menu item, which pops up the new/Select Database Connection window, as shown in 2.17.

Figure 2.17 Creating a new connection

(2) If you want to create a database connection to the System user scheme in an Oracle database, you need to fill in the following in Figure 2.18:

"Connection Name" Enter a custom connection name, such as System_ora;

Enter system in User name, and enter the appropriate password in password;

Select the Keep password check box;

The "Role" column is left as the default;

In the Hostname field, enter the hostname or leave it as localhost;

The port value is left at the default of 1521;

Enter the SID of the database in the "Sid" field, as the system flag for this database is ORCL.

When you have finished setting up, click the test button to test whether the setting is connected, and if it succeeds, it will show "success" after the left corner status.

Figure 2.18 The new/Select Database Connection window

Common error: If the connection error shown in 2.19 appears, Oracle's service is not turned on.

Figure 2.19 A connection error occurred

Learn two more tricks: the steps to turn on Oracle services are as follows.

(1) Right-click on the "Computer" icon in the desktop and select "Manage".

(2) In the Computer Management interface, click the Services option under services and applications.

(3) In the services, locate the Oracle-related services, right-click, select "On" to open the selected service, 2.20 shows.

Figure 2.20 Turning on Oracle Services

All services starting with "Oracle" are turned on, as shown in 2.21.

Figure 2.21 All open Oracle Services

(3) Click the "Save" button to save the test successful connection for later use. A database connection named System_ora appears under the connection node of the main interface, and clicking on the "+" in front of the connection will appear in the subdirectory, displaying the database objects that can be manipulated in the subdirectory, as shown in 2.22, after which all operations on the Oracle database can be completed under that interface.

Figure 2.22 The newly created database connection System_ora

Note: To make a database connection, you must open the database's listening service (Oracleoradb12home1thslistener) and the database's primary service (ORACLESERVICEMLDN).

How to create a database connection using SQL Developer