Simple examples, showing how to connect to ORACLE DB, with Java ojdbc driver, and how to make inserts without polluting ORACLE environment.

It's important to understand that polluting the ORACLE environment, without closing the opened connection, at the end, it will lock the system.

• Examples
• Compatibility
• Install
• Configure
• Compile
• Run
• Monitor
• Disclaimer
• Donations

The examples are:

• HelloWorld: Just a simple query to table DUAL;
• WrongWay: Inserts data in table TEST_INSERT, in wrong way: opens the connection for each insert, without closing the connection. Because of that it's polluting the ORACLE environment with tons of SESSIONS_PER_USER, until the system resources run out!
• CorrectWay: Just closes the balanced connection with the open ones. At least it's not polluting the ORACLE environment; but it's unnecessary opening and closing the connection for each insert;
• GoodWay: Opens the connection to ORACLE only one time, closing it only one time at the end of the program;
• BetterWay: One connection, one commit.

Tested on:

• macOS Mojave 10.14.6
  • java: 1.8.0_66
  • javac: 1.8.0_66
• Oracle Linux Server 7.5
  • Oracle Database 18c Express Edition
  • java: 1.8.0_151
  • javac 1.8.0_151

Download ojdbc7.jar from jdbc-drivers-12c-downloads and copy it in lib/ folder.

To run the examples WrongWay, CorrectWay, GoodWay, BetterWay, execute the script in sql/create-table_test_insert.sql; it will create the table TEST_INSERT in your DB.

Copy Configure/Credentials-template.java to Configure/Credentials.java and modify the credentials you need (url, user and password).

$ cd examples/HelloWorld

$ . ../../script/compile.sh

. ../../script/run.sh

To monitor the SESSIONS_PER_USER execute the query in sql/sessions_per_user.sql

MonitorWrongWay,: 61 SESSIONS_PER_USER polluting ORACLE environment:

MonitorCorrectWay: just 3 SESSIONS_PER_USER:

Don't use this repo in production, it's only an academic collection of examples; production is on another layer. Use at your own risk.

Donations are welcome at Bitcoin address: 1Java1MmYqF3hTQmvwjtT3k8Dbc6HHd7Tv