0) Install ISQL

If you’re on macOS the easiest way to install isql is using homebrew brew install unixodbc.

1) Download drivers

1. Download ODBC Package & Basic Package from here
2. Create an oracle account if necessary

2) Prepare driver files

1. cd Downloads
2. unzip instantclient-basic-macos.x64-19.3.0.0.0dbru.zip
3. unsip instantclient-odbc-macos.x64-19.3.0.0.0dbru.zip
4. mkdir ~/lib
5. mkdir -p /opt/oracle/
6. mv $(pwd)/instantclient_19_3 /opt/oracle/
7. ln -s /opt/oracle/instantclient_19_3/libclntsh.dylib.19.1 /opt/oracle/instantclient_19_3/libclntshcore.dylib.19.1 ~/lib

3) Update ODBC ini files

1. update odbcinst.ini to add

   [ODBC Drivers]
   Oracle ODBC Driver = Installed
   ...
   ...
   [Oracle ODBC Driver]
   Description = Oracle 19 ODBC driver
   Driver      = /opt/oracle/instantclient_19_3/libsqora.dylib.19.1
   Setup       =
   FileUsage   =
   CPTimeout   =
   CPReuse     =
   

2. Update odbc.ini to add

   [ODBC Data Sources]
   {dsn_name} = [Oracle ODBC Driver]
   ...
   ...
   [{dsn_name}]
   AggregateSQLType=FLOAT
   Application Attributes=T
   Attributes=W
   BatchAutocommitMode=IfAllSuccessful
   BindAsFLOAT=F
   CacheBufferSize=20
   CloseCursor=F
   DisableDPM=F
   DisableMTS=T
   DisableRULEHint=T
   Driver=/opt/oracle/instantclient_19_3/libsqora.dylib.19.1
   DSN={dsn_name}
   EXECSchemaOpt=
   EXECSyntax=T
   Failover=T
   FailoverDelay=10
   FailoverRetryCount=10
   FetchBufferSize=64000
   ForceWCHAR=F
   LobPrefetchSize=8192
   Lobs=T
   Longs=T
   MaxLargeData=0
   MaxTokenSize=8192
   MetadataIdDefault=F
   QueryTimeout=T
   ResultSets=T
   ServerName={host}:{port}/{server}
   SQLGetData extensions=F
   SQLTranslateErrors=F
   StatementCache=F
   Translation DLL=
   Translation Option=0
   UseOCIDescribeAny=F
   UserID={username}
   Password={password}
   

4) Verify installation

1. Verify by connecting isql -v {dsn_name}
2. Note: on macOS Catalina or later you may have to workaround the lack of notarization by navigating to “system preferences>security>allow” and approving multiple files after multiple connection attempts using step 4.1