Obtaining a Driver Package, a Dependent Library, and Header Files

Obtaining the Driver Package

Download the driver package and its verification package listed in Table 1.

**Table 1** Driver package download list
Version	Download Address
V2.0-8.x	Driver package Verification package for the driver package

To prevent a software package from being tampered with during transmission or storage, download the corresponding verification package and perform the following steps to verify the software package:

Verifying the software package integrity on a Linux server:
1. Upload the software package and verification package to the same directory on the VM.
2. Run the following command to verify the integrity of the software package:
  cat GaussDB_driver.zip.sha256 | sha256sum --check
  
  If OK is displayed in the command output, the verification is successful.
```
GaussDB_driver.zip: OK
```

Verifying the software package integrity on a Windows server:
1. Press Win+R to open the Run dialog box. Type cmd in the text box and press Enter to open the Command Prompt window.
2. Run the following command to obtain the hash value of the driver package:
  certutil -hashfile {local_directory_of_the_driver_package}\{driver_package_name} sha256
  - Replace {local_directory_of_the_driver_package} with the actual download path, for example, C:\Users.
  - Replace {driver_package_name} with the name of the downloaded driver package, for example, GaussDB_driver.zip.
  Example: certutil -hashfile C:\Users\GaussDB_driver.zip sha256
3. Compare the hash value obtained in 2 with the hash value of the verification package obtained in Table 1.
  - If they are consistent, the verification is successful.
  - If they are inconsistent, download the driver package again and repeat 1 to 3 to verify the driver package.

Obtain a dependent library and header files of libpq from GaussDB-Kernel_Database version number_OS version number_64bit_Libpq.tar.gz or GaussDB-Kernel_Database version number_OS version number_64bit_Libpq_Static.tar.gz in the driver package. The required header file is stored in the include folder, and the lib folder contains the required libpq library file. Programs that use libpq must include the header file libpq-fe.h and must connect to the libpq library.

In addition to libpq-fe.h, the include folder contains the header files postgres_ext.h, gs_thread.h, and gs_threadlocal.h by default. These three header files are the dependency files of libpq-fe.h.

The functions of the Libpq_Static driver package are the same as those of the libpq driver package. You can select a proper libpq.so library based on the actual application scenario. Differences are as follows:

The libpq.so file in the libpq driver package dynamically links the OpenSSL libraries (libssl.so and libcrypto.so).
The libpq.so file in the Libpq_Static driver package is statically linked to the OpenSSL libraries to resolve the conflict caused by inconsistency between the OpenSSL version provided by the OS and that provided by the OS in some customer scenarios.