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  1. <?xml version="1.0" encoding="UTF-8" standalone="no"?>

  2. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>1.3. Creating a Database</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets V1.79.1" /><link rel="prev" href="tutorial-arch.html" title="1.2. Architectural Fundamentals" /><link rel="next" href="tutorial-accessdb.html" title="1.4. Accessing a Database" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">1.3. Creating a Database</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="tutorial-arch.html" title="1.2. Architectural Fundamentals">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="tutorial-start.html" title="Chapter 1. Getting Started">Up</a></td><th width="60%" align="center">Chapter 1. Getting Started</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 12.4 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="tutorial-accessdb.html" title="1.4. Accessing a Database">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="TUTORIAL-CREATEDB"><div class="titlepage"><div><div><h2 class="title" style="clear: both">1.3. Creating a Database</h2></div></div></div><a id="id-1.4.3.4.2" class="indexterm"></a><a id="id-1.4.3.4.3" class="indexterm"></a><p>

  3.     The first test to see whether you can access the database server

  4.     is to try to create a database.  A running

  5.     <span class="productname">PostgreSQL</span> server can manage many

  6.     databases.  Typically, a separate database is used for each

  7.     project or for each user.

  8.    </p><p>

  9.     Possibly, your site administrator has already created a database

  10.     for your use.  In that case you can omit this step and skip ahead

  11.     to the next section.

  12.    </p><p>

  13.     To create a new database, in this example named

  14.     <code class="literal">mydb</code>, you use the following command:

  15. </p><pre class="screen">

  16. <code class="prompt">$</code> <strong class="userinput"><code>createdb mydb</code></strong>

  17. </pre><p>

  18.     If this produces no response then this step was successful and you can skip over the

  19.     remainder of this section.

  20.    </p><p>

  21.     If you see a message similar to:

  22. </p><pre class="screen">

  23. createdb: command not found

  24. </pre><p>

  25.     then <span class="productname">PostgreSQL</span> was not installed properly.  Either it was not

  26.     installed at all or your shell's search path was not set to include it.

  27.     Try calling the command with an absolute path instead:

  28. </p><pre class="screen">

  29. <code class="prompt">$</code> <strong class="userinput"><code>/usr/local/pgsql/bin/createdb mydb</code></strong>

  30. </pre><p>

  31.     The path at your site might be different.  Contact your site

  32.     administrator or check the installation instructions to

  33.     correct the situation.

  34.    </p><p>

  35.     Another response could be this:

  36. </p><pre class="screen">

  37. createdb: could not connect to database postgres: could not connect to server: No such file or directory

  38.         Is the server running locally and accepting

  39.         connections on Unix domain socket "/tmp/.s.PGSQL.5432"?

  40. </pre><p>

  41.     This means that the server was not started, or it was not started

  42.     where <code class="command">createdb</code> expected it.  Again, check the

  43.     installation instructions or consult the administrator.

  44.    </p><p>

  45.     Another response could be this:

  46. </p><pre class="screen">

  47. createdb: could not connect to database postgres: FATAL:  role "joe" does not exist

  48. </pre><p>

  49.     where your own login name is mentioned.  This will happen if the

  50.     administrator has not created a <span class="productname">PostgreSQL</span> user account

  51.     for you.  (<span class="productname">PostgreSQL</span> user accounts are distinct from

  52.     operating system user accounts.)  If you are the administrator, see

  53.     <a class="xref" href="user-manag.html" title="Chapter 21. Database Roles">Chapter 21</a> for help creating accounts.  You will need to

  54.     become the operating system user under which <span class="productname">PostgreSQL</span>

  55.     was installed (usually <code class="literal">postgres</code>) to create the first user

  56.     account.  It could also be that you were assigned a

  57.     <span class="productname">PostgreSQL</span> user name that is different from your

  58.     operating system user name; in that case you need to use the <code class="option">-U</code>

  59.     switch or set the <code class="envar">PGUSER</code> environment variable to specify your

  60.     <span class="productname">PostgreSQL</span> user name.

  61.    </p><p>

  62.     If you have a user account but it does not have the privileges required to

  63.     create a database, you will see the following:

  64. </p><pre class="screen">

  65. createdb: database creation failed: ERROR:  permission denied to create database

  66. </pre><p>

  67.     Not every user has authorization to create new databases.  If

  68.     <span class="productname">PostgreSQL</span> refuses to create databases

  69.     for you then the site administrator needs to grant you permission

  70.     to create databases.  Consult your site administrator if this

  71.     occurs.  If you installed <span class="productname">PostgreSQL</span>

  72.     yourself then you should log in for the purposes of this tutorial

  73.     under the user account that you started the server as.

  74. 

  75.     <a href="#ftn.id-1.4.3.4.10.4" class="footnote"><sup class="footnote" id="id-1.4.3.4.10.4">[1]</sup></a>

  76.    </p><p>

  77.     You can also create databases with other names.

  78.     <span class="productname">PostgreSQL</span> allows you to create any

  79.     number of databases at a given site.  Database names must have an

  80.     alphabetic first character and are limited to 63 bytes in

  81.     length.  A convenient choice is to create a database with the same

  82.     name as your current user name.  Many tools assume that database

  83.     name as the default, so it can save you some typing.  To create

  84.     that database, simply type:

  85. </p><pre class="screen">

  86. <code class="prompt">$</code> <strong class="userinput"><code>createdb</code></strong>

  87. </pre><p>

  88.    </p><p>

  89.     If you do not want to use your database anymore you can remove it.

  90.     For example, if you are the owner (creator) of the database

  91.     <code class="literal">mydb</code>, you can destroy it using the following

  92.     command:

  93. </p><pre class="screen">

  94. <code class="prompt">$</code> <strong class="userinput"><code>dropdb mydb</code></strong>

  95. </pre><p>

  96.     (For this command, the database name does not default to the user

  97.     account name.  You always need to specify it.)  This action

  98.     physically removes all files associated with the database and

  99.     cannot be undone, so this should only be done with a great deal of

  100.     forethought.

  101.    </p><p>

  102.     More about <code class="command">createdb</code> and <code class="command">dropdb</code> can

  103.     be found in <a class="xref" href="app-createdb.html" title="createdb"><span class="refentrytitle"><span class="application">createdb</span></span></a> and <a class="xref" href="app-dropdb.html" title="dropdb"><span class="refentrytitle"><span class="application">dropdb</span></span></a>

  104.     respectively.

  105.    </p><div class="footnotes"><br /><hr style="width:100; text-align:left;margin-left: 0" /><div id="ftn.id-1.4.3.4.10.4" class="footnote"><p><a href="#id-1.4.3.4.10.4" class="para"><sup class="para">[1] </sup></a>

  106.       As an explanation for why this works:

  107.       <span class="productname">PostgreSQL</span> user names are separate

  108.       from operating system user accounts.  When you connect to a

  109.       database, you can choose what

  110.       <span class="productname">PostgreSQL</span> user name to connect as;

  111.       if you don't, it will default to the same name as your current

  112.       operating system account.  As it happens, there will always be a

  113.       <span class="productname">PostgreSQL</span> user account that has the

  114.       same name as the operating system user that started the server,

  115.       and it also happens that that user always has permission to

  116.       create databases.  Instead of logging in as that user you can

  117.       also specify the <code class="option">-U</code> option everywhere to select

  118.       a <span class="productname">PostgreSQL</span> user name to connect as.

  119.      </p></div></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="tutorial-arch.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="tutorial-start.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="tutorial-accessdb.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">1.2. Architectural Fundamentals </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> 1.4. Accessing a Database</td></tr></table></div></body></html>
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