[大数据]QOCI for the Oracle Call Interface (OCI)

The Qt OCI plugin supports Oracle 9i, 10g and higher. After connecting to the Oracle server, the plugin will auto-detect the database version and enable features accordingly.

It's possible to connect to a Oracle database without a tnsnames.ora file. This requires that the database SID is passed to the driver as the database name, and that a hostname is given.

OCI User Authentication

The Qt OCI plugin supports authentication using external credentials (OCI_CRED_EXT). Usually, this means that the database server will use the user authentication provided by the operating system instead of its own authentication mechanism.

Leave the username and password empty when opening a connection with?QSqlDatabase?to use the external credentials authentication.

OCI BLOB/LOB Support

Binary Large Objects (BLOBs) can be read and written, but be aware that this process may require a lot of memory. You should use a forward only query to select LOB fields (see?QSqlQuery::setForwardOnly()).

Inserting BLOBs should be done using either a prepared query where the BLOBs are bound to placeholders or?QSqlTableModel, which uses a prepared query to do this internally.

How to Build the OCI Plugin on Unix and macOS

For Oracle 10g, all you need is the "Instant Client Package - Basic" and "Instant Client Package - SDK". For Oracle prior to 10g, you require the standard Oracle client and the SDK packages.

Oracle library files required to build the driver:

• libclntsh.so?(all versions)
• libwtc9.so?(only Oracle 9)

Tell?qmake?where to find the Oracle header files and shared libraries and run make:

For Oracle version 9:

cd $QTDIR/qtbase/src/plugins/sqldrivers
qmake -- OCI_INCDIR="$ORACLE_HOME/rdbms/public" OCI_LIBDIR="$ORACLE_HOME/lib" OCI_LIBS="-lclntsh -lwtc9"
make sub-oci

For Oracle version 10, we assume that you installed the RPM packages of the Instant Client Package SDK (you need to adjust the version number accordingly):

cd $QTDIR/qtbase/src/plugins/sqldrivers
qmake -- OCI_INCDIR=/usr/include/oracle/10.1.0.3/client OCI_LIBDIR=/usr/lib/oracle/10.1.0.3/client/lib
make sub-oci

Note:?If you are using the Oracle Instant Client package, you will need to set LD_LIBRARY_PATH when building the OCI SQL plugin, and when running an application that uses the OCI SQL plugin. You can avoid this requirement by setting RPATH, and listing all of the libraries to link to. Here is an example:

configure OCI_INCDIR=/usr/include/oracle/10.1.0.3/client OCI_LIBDIR=/usr/lib/oracle/10.1.0.3/client/lib -R /usr/lib/oracle/10.1.0.3/client/lib OCI_LIBS="-lclntsh -lnnz10"
make

If you wish to build the OCI plugin manually with this method, the procedure looks like this:

cd $QTDIR/qtbase/src/plugins/sqldrivers
qmake -- OCI_INCDIR=/usr/include/oracle/10.1.0.3/client OCI_LIBDIR=/usr/lib/oracle/10.1.0.3/client/lib OCI_LIBS="-Wl,-rpath,/usr/lib/oracle/10.1.0.3/client/lib -lclntsh -lnnz10"
make sub-oci

How to Build the OCI Plugin on Windows

Choosing the option "Programmer" in the Oracle Client Installer from the Oracle Client Installation CD is generally sufficient to build the plugin. For some versions of Oracle Client, you may also need to select the "Call Interface (OCI)" option if it is available.

Build the plugin as follows (here it is assumed that Oracle Client is installed in?C:\oracle):

cd %QTDIR%\qtbase\src\plugins\sqldrivers
qmake -- OCI_INCDIR=c:/oracle/oci/include OCI_LIBDIR=c:/oracle/oci/lib/msvc
nmake sub-oci

If you are not using a Microsoft compiler, replace?nmake?with?mingw32-make?in the line above.

When you run your application, you will also need to add the?oci.dll?path to your?PATH?environment variable:

set PATH=%PATH%;c:\oracle\bin