Linux DSN Configuration

This section shows how to connect to MongoDB and execute SQL queries from several Linux distributions: Debian-based systems, like Ubuntu, and Red Hat Linux platforms, like Red Hat Enterprise Linux (RHEL), CentOS, and Fedora.

Using a Driver Manager

Before installing the CData ODBC Driver for MongoDB 2016 on Linux, you will need to install a driver manager. ODBC-compliant applications connect to the driver through a driver manager. After you connect, the driver manager loads the driver and passes function calls from the application to the driver. The driver manager also implements some functions for discovering the registered drivers and DSNs. DSNs can be defined for a specific user or system wide.

Installing unixODBC

Precompiled binaries for the unixODBC driver manager are available for many operating systems.

On Debian-based systems like Ubuntu, you can install unixODBC by running the following command as root or with sudo:

apt-get install unixODBC unixODBC-dev

On Red Hat Enterprise Linux, CentOS, and Fedora, you can install unixODBC with YUM or DNF. For example, run the following command as root or with sudo:

yum install unixODBC unixODBC-devel

If binaries are not available for your operating system, you will need to compile unixODBC yourself. Please refer to the unixODBC website for more information about obtaining binaries or compiling unixODBC on your operating system.

Installing the Driver Dependencies

Minimum Linux Versions

Below are the minimum supported versions for Red Hat-based and Debian-based systems:


OS	Min. Version
Ubuntu	11
Debian	7
RHEL	6
CentOS	6
Fedora	13

Required Libraries and Packages

Below are the libraries required by the driver and their corresponding packages:


Debian/Ubuntu Package	RHEL/CentOS/Fedora Package	File
libc6	glibc	linux-vdso.1
libc6	glibc	libm.so.6
libc6	glibc	librt.so.1
libc6	glibc	libdl.so.2
libc6	glibc	libpthread.so.0
libc6	glibc	libc.so.6
libc6	glibc	ld-linux-x86-64.so.2
libstdc++6	libstdc++	libstdc++.so.6
zlib1g	zlib	libz.so.1
libgcc1	libgcc	libgcc_s.so.1

Installing the Packages

You can install the necessary dependencies with the following commands:

Debian/Ubuntu:

apt-get install libc6 libstdc++6 zlib1g libgcc1

RHEL/CentOS/Fedora:
```
yum install glibc libstdc++ zlib libgcc
```

Installing the Driver

You can use standard package management systems to easily and quickly install the driver.

On Debian-based systems, like Ubuntu, you can install the driver by running the following command as root or with sudo:

dpkg -i /path/to/.deb

On systems that support the RPM package format, you can install the driver by running the following command as root or with sudo:

rpm -Uvh /path/to/.rpm

Using the unixODBC Configuration Files

You can determine the location of the configuration files on your system by entering the following command into a terminal:

odbcinst -j

Below is an example of the output of this command:

DRIVERS............: /etc/odbcinst.ini
SYSTEM DATA SOURCES: /etc/odbc.ini
FILE DATA SOURCES..: /etc/ODBCDataSources
USER DATA SOURCES..: /home/myuser/.odbc.ini
SQLULEN Size.......: 8
SQLLEN Size........: 8
SQLSETPOSIROW Size.: 8

The driver installation registers the driver for system-wide use and creates a system DSN with empty values for commonly required properties. Modifying unixODBC's system-wide settings requires elevated permissions; to do so, you can use root or the sudo command.

Configuring a DSN

ODBC data sources are defined in sections in the odbc.ini file.

In addition to the connection properties required to connect to your data source, the Driver property specifies either a driver definition in the odbcinst.ini file or the path to the driver library.

[CData MongoDB Source]
Driver = CData ODBC Driver for MongoDB
Description = My Description
MyConnectionProperty1 = My Value
MyConnectionProperty2 = My Value2

You can list the data sources on your system with the following command:

odbcinst  -q -s

Connecting to MongoDB

Set the following connection properties to connect to a single MongoDB instance:

Server: Set this to the name or address of the server your MongoDB instance is running on. You can specify the port here or in Port.
Database: Set this to the database you want to read from and write to.

Connecting to Replica Sets

To connect to a replica set, set the following in addition to the preceding connection properties:

ReplicaSet: Set this to a comma-separated list of secondary servers in the replica set, specified by address and port.
SlaveOK: Set this to true if you want to read from secondary (slave) servers.
ReadPreference: Set this to fine-tune how the driver reads from secondary servers.

Securing MongoDB Connections

You can set UseSSL to negotiate SSL/TLS encryption when you connect.

Authenticating MongoDB Connections

Supported authentication types are challenge-response authentication and LDAP. To authenticate to MongoDB, select an authentication type in AuthMechanism and set User and Password. If you need to work with data in one database and authenticate to another database, set AuthDatabase in addition to Database.

Configuring Driver Definitions

The sections of the odbcinst.ini file map a driver name to the driver library. The section begins with the driver name; the Driver property points to the path to the driver library. The driver library is the .so file located by default in /opt/cdata/mongodb/lib. A Description property can also be provided.

You can list the drivers installed on the system with the following command:

odbcinst -q -d

Testing the Connection

You can use isql, included with unixODBC, to execute SQL queries to MongoDB from the command line. When testing the connection, use the -v flag to output any messages from the driver manager and the driver.

isql -v "CData MongoDB Source"