# Python example connection_string = "hr/your_password@//192.168.1.100:1521/orcl" Using SQL*Plus (if installed) sqlplus system@//dbserver:1521/orcl Using PowerShell (Windows) # Test OCI DLL loading Add-Type -Path "C:\oracle\instantclient_32_19\Oracle.DataAccess.dll" $conn = New-Object Oracle.DataAccess.Client.OracleConnection("Data Source=//dbserver:1521/orcl;User Id=hr;Password=pass") $conn.Open() $conn.State Using Python (cx_Oracle) import cx_Oracle # Point to 32-bit Instant Client cx_Oracle.init_oracle_client(lib_dir=r"C:\oracle\instantclient_32_19") conn = cx_Oracle.connect("hr/pass@//dbserver:1521/orcl") print(cx_Oracle.clientversion()) 6. Common Issues & Solutions | Issue | Solution | |-------|----------| | "ORA-12541: TNS:no listener" | Check DB listener is running and firewall allows port 1521 | | "The specified module could not be found" | Missing Visual C++ Redistributable (Windows) – install VC++ 2015-2022 x86 | | "Wrong ELF class: ELFCLASS64" | Trying to use 64-bit Instant Client with 32-bit app – download correct 32-bit version | | "ORA-01804: timeout" | Set TNS_ADMIN environment variable to folder containing tnsnames.ora | | "DLL load failed" in Python | Python must be 32-bit: python -c "import struct; print(struct.calcsize('P')*8)" → should print 32 | 7. Version Compatibility | Oracle DB Version | Recommended Instant Client | |-------------------|----------------------------| | 21c (21.x) | 21.x (or 19.x for backward compat) | | 19c | 19.x (or 12.2) | | 12c | 12.2 or 12.1 | | 11g | 11.2 (no longer supported, use 19.x if possible) |
# Remove from PATH # Delete folder: C:\oracle\instantclient_32_19 oracle instant client 32 bit
rm -rf /opt/oracle/instantclient_32_19 # Remove LD_LIBRARY_PATH from .bashrc ✅ Download 32-bit (x86) package, not x64 ✅ Extract to a simple path (no spaces) ✅ Install VC++ Redistributable (Windows) or libaio (Linux) ✅ Add Instant Client directory to PATH/LD_LIBRARY_PATH ✅ Set TNS_ADMIN if using tnsnames.ora ✅ Test with SQL*Plus or simple script ✅ Verify your app is truly 32-bit Need the latest version? Oracle 19c is the final 32-bit release (ended support in April 2024). For new projects, migrate to 64-bit when possible. # Python example connection_string = "hr/your_password@//192
# C:\oracle\instantclient_32_19\tnsnames.ora MYDB = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = dbserver.company.com)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = orcl) ) ) Oracle 19c is the final 32-bit release (ended
A lightweight set of Oracle libraries, tools, and binaries that allows 32-bit applications to connect to Oracle databases without a full Oracle client installation .