We are using the PostgreSQL database management system (which will often be referred to simply as "Postgres"). PostgreSQL is an open-source DBMS with a very long history of research and development.
This document provides information on using the PostgreSQL system and provides references to relevant documentation.
Note: we are currently running version 9.x of PostgreSQL; choose tools accordingly.
Creating a PostgreSQL Account
In order to access PostgreSQL, you will need to create an account with the
DBMS itself. Using this form you can
select a database username and password for PostgreSQL access. Please be
aware that PostgreSQL accounts are generally valid for particular classes
only and may deleted at the end of any given semester
without additional notice. In other words, do not assume your PostgreSQL
account will continue to exist for any length of time beyond a given
Getting Started with PostgreSQL
The PostgreSQL database server runs as a daemon process on a local
Linux/UNIX server (e.g., dhansen.cs.georgefox.edu)
To access a PostgreSQL database you must either use an interactive tool or embedded-language interfaces - see the section on accessing PostgreSQL from application programs for more information on client tools you can install.
I have installed a web-based portal for accessing the databases on my server. You can log in using the database account you created per the instructions above.
PostgreSQL provides a command-line client interface - psql You can use this on most any system that has the PostgreSQL client tools installed. However, you may find one of the GUI-clients easier to use - see section on Useful Tools below.
Here is a quick tutorial on using the PostgreSQL DBMS via the command-line interface that should be sufficient to get you started. Note that the commands and SQL shown below can be entered into most any client, command-line or GUI.
The easiest way to access PostgreSQL databases is via the interactive SQL command-line client program called psql
$ psql -U dhansen -h dhansen.cs.georgefox.edu companyat the command prompt (Note: you need to provide different values for the username, database name, and hostname depending on who you are and where the PostgreSQL server is running).
To learn the full syntax of the psql command, use the --help flag when you execute the program:
$ psql --help psql is the PostgreSQL interactive terminal. Usage: psql [OPTION]... [DBNAME [USERNAME]] General options: -c, --command=COMMAND run only single command (SQL or internal) and exit -d, --dbname=DBNAME database name to connect to (default: "dhansen") -f, --file=FILENAME execute commands from file, then exit -l, --list list available databases, then exit -v, --set=, --variable=NAME=VALUE set psql variable NAME to VALUE -X, --no-psqlrc do not read startup file (~/.psqlrc) -1 ("one"), --single-transaction execute command file as a single transaction --help show this help, then exit --version output version information, then exit Input and output options: -a, --echo-all echo all input from script -e, --echo-queries echo commands sent to server -E, --echo-hidden display queries that internal commands generate -L, --log-file=FILENAME send session log to file -n, --no-readline disable enhanced command line editing (readline) -o, --output=FILENAME send query results to file (or |pipe) -q, --quiet run quietly (no messages, only query output) -s, --single-step single-step mode (confirm each query) -S, --single-line single-line mode (end of line terminates SQL command) Output format options: -A, --no-align unaligned table output mode -F, --field-separator=STRING set field separator (default: "|") -H, --html HTML table output mode -P, --pset=VAR[=ARG] set printing option VAR to ARG (see \pset command) -R, --record-separator=STRING set record separator (default: newline) -t, --tuples-only print rows only -T, --table-attr=TEXT set HTML table tag attributes (e.g., width, border) -x, --expanded turn on expanded table output Connection options: -h, --host=HOSTNAME database server host or socket directory (default: "local socket") -p, --port=PORT database server port (default: "5432") -U, --username=USERNAME database user name (default: "dhansen") -w, --no-password never prompt for password -W, --password force password prompt (should happen automatically) For more information, type "\?" (for internal commands) or "\help" (for SQL commands) from within psql, or consult the psql section in the PostgreSQL documentation. Report bugs to <firstname.lastname@example.org>.
NOTE: I have activated the access-control mechanisms of PostgreSQL. You must provide a username using the -U switch which tells psql to prompt you for a password for authorization.
To access a database, run psql as demonstrated here.
psql is a simple, interactive SQL front-end to PostgreSQL. You type SQL statements (use as many lines as you want), end them with either \g or a semi-colon (;), and PostgreSQL executes the query and the results are displayed by psql.
To quit a psql session type \q.
You can get help on psql commands with the \? command, and you can get help on SQL by typing \h.
Downloading Useful Tools
There are a variety of clients available for PostgreSQL.
Here is a list of GUI tools. Some, such as the SQL Workbench, will require you
to download the Java JDBC driver as well - see below.
As noted above, I have provided a server-side web-based portal for accessing my server. This portal provides the same sort of GUI access that many of these client-side tools provide.
To create or destroy a database you issue "queries" to the database
(e.g., from psql):
company=> create database mydatabase; company=> drop database mydatabase;Note that you can not destroy a database you're currently working with. You can use the \c dbname command to change the database you are working with (you can always set your current database to the pre-existing template1 database initially, until you create your own database).
Accessing PostgreSQL from Application Programs
A PostgreSQL database can be accessed by programs written in a number
of languages including C/C++, Java, PHP, PERL, etc. An
ODBC (open-database connectivity) interface is also
available. The ODBC and JDBC
interfaces should be usable from a variety of computer systems.
Below are links to relevant resources. These interfaces may prove
useful to you for implementing application programs to load and access
postgresql.jarand that it is located in the same directory as
JDBCExample.java), you should be able to execute this program with:
$ java -cp .:postgresql.jar JDBCExample
C:\> java -cp .;postgresql.jar JDBCExamplefor Windows (note the use of the ';' character in the classpath)
When using Windows, you may also need to specify the entire path to
Note that these programs and scripts include a database username and password! Protection of source-code is vital when your code includes authentication information.
PostgreSQL documentation is available
In addition, many of the PostgreSQL commands are available as man pages:
$ man createdband psql includes on-line help for relevant commands as well as SQL syntax via the
PostgreSQL Caveats and Bugs
Last modified: , by David M. Hansen