Sample tnsnames.ora :
from Oracle Technology Network (OTN) – free for development and production use with a valid Oracle Database license. Version note: As of 2026, Oracle recommends moving to Instant Client 23 for new projects, but Instant Client 19 remains fully supported and widely used in production environments due to its long-term stability.
sqlplus scott/tiger@MYDB One of the strongest points of Instant Client is its compatibility with popular languages: oracle instant client 19
| Language | Driver/Module | How it uses Instant Client | |----------|--------------|----------------------------| | Python | cx_Oracle / python-oracledb (Thick mode) | Requires Oracle client libraries | | Node.js | node-oracledb | Thick mode uses Instant Client | | PHP | oci8 extension | Requires Instant Client | | Ruby | ruby-oci8 | Links to Instant Client libs | | Go | goracle / go-oci8 | Uses OCI libraries | | .NET | ODP.NET Managed Driver | No client needed; Unmanaged requires IC | | Java | JDBC Thin | No client needed; OCI driver uses IC |
MYDB = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = dbserver.example.com)(PORT = 1521)) (CONNECT_DATA = (SERVICE_NAME = orclpdb)) ) Then connect: Sample tnsnames
Example: Python with python-oracledb (thick mode)
In the world of enterprise database management, Oracle Database remains a dominant force. However, installing the full Oracle Database client (often several gigabytes) just to connect an application or run a basic SQL script is overkill. Enter Oracle Instant Client 19 —a lightweight, easy-to-deploy solution that provides the necessary network connectivity and tools to interact with Oracle Databases. What is Oracle Instant Client? Oracle Instant Client is a set of shared libraries, binaries, and configuration files that allow applications to connect to local or remote Oracle Database instances without installing the full, heavyweight Oracle Home. First introduced in the mid-2000s, it has become the standard for developers, DevOps engineers, and system administrators who need a minimal footprint. However, installing the full Oracle Database client (often
sqlplus scott/tiger@//192.168.1.100:1521/ORCLPDB1 Create a tnsnames.ora file in a directory (e.g., /etc/oracle or %USERPROFILE%\oracle ). Set TNS_ADMIN to that directory.