doc/src/sgml/ref/create_database.sgml

   1 <!--
   2 doc/src/sgml/ref/create_database.sgml
   3 PostgreSQL documentation
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   5
   6 <refentry id="sql-createdatabase">
   7  <indexterm zone="sql-createdatabase">
   8   <primary>CREATE DATABASE</primary>
   9  </indexterm>
  10
  11  <refmeta>
  12   <refentrytitle>CREATE DATABASE</refentrytitle>
  13   <manvolnum>7</manvolnum>
  14   <refmiscinfo>SQL - Language Statements</refmiscinfo>
  15  </refmeta>
  16
  17  <refnamediv>
  18   <refname>CREATE DATABASE</refname>
  19   <refpurpose>create a new database</refpurpose>
  20  </refnamediv>
  21
  22  <refsynopsisdiv>
  23 <synopsis>
  24 CREATE DATABASE <replaceable class="parameter">name</replaceable>
  25     [ WITH ] [ OWNER [=] <replaceable class="parameter">user_name</replaceable> ]
  26            [ TEMPLATE [=] <replaceable class="parameter">template</replaceable> ]
  27            [ ENCODING [=] <replaceable class="parameter">encoding</replaceable> ]
  28            [ STRATEGY [=] <replaceable class="parameter">strategy</replaceable> ]
  29            [ LOCALE [=] <replaceable class="parameter">locale</replaceable> ]
  30            [ LC_COLLATE [=] <replaceable class="parameter">lc_collate</replaceable> ]
  31            [ LC_CTYPE [=] <replaceable class="parameter">lc_ctype</replaceable> ]
  32            [ BUILTIN_LOCALE [=] <replaceable class="parameter">builtin_locale</replaceable> ]
  33            [ ICU_LOCALE [=] <replaceable class="parameter">icu_locale</replaceable> ]
  34            [ ICU_RULES [=] <replaceable class="parameter">icu_rules</replaceable> ]
  35            [ LOCALE_PROVIDER [=] <replaceable class="parameter">locale_provider</replaceable> ]
  36            [ COLLATION_VERSION = <replaceable>collation_version</replaceable> ]
  37            [ TABLESPACE [=] <replaceable class="parameter">tablespace_name</replaceable> ]
  38            [ ALLOW_CONNECTIONS [=] <replaceable class="parameter">allowconn</replaceable> ]
  39            [ CONNECTION LIMIT [=] <replaceable class="parameter">connlimit</replaceable> ]
  40            [ IS_TEMPLATE [=] <replaceable class="parameter">istemplate</replaceable> ]
  41            [ OID [=] <replaceable class="parameter">oid</replaceable> ]
  42 </synopsis>
  43  </refsynopsisdiv>
  44
  45  <refsect1>
  46   <title>Description</title>
  47
  48   <para>
  49    <command>CREATE DATABASE</command> creates a new
  50    <productname>PostgreSQL</productname> database.
  51   </para>
  52
  53   <para>
  54    To create a database, you must be a superuser or have the special
  55    <literal>CREATEDB</literal> privilege.
  56    See <xref linkend="sql-createrole"/>.
  57   </para>
  58
  59   <para>
  60    By default, the new database will be created by cloning the standard
  61    system database <literal>template1</literal>.  A different template can be
  62    specified by writing <literal>TEMPLATE
  63    <replaceable class="parameter">name</replaceable></literal>.  In particular,
  64    by writing <literal>TEMPLATE template0</literal>, you can create a pristine
  65    database (one where no user-defined objects exist and where the system
  66    objects have not been altered)
  67    containing only the standard objects predefined by your
  68    version of <productname>PostgreSQL</productname>.  This is useful
  69    if you wish to avoid copying
  70    any installation-local objects that might have been added to
  71    <literal>template1</literal>.
  72   </para>
  73  </refsect1>
  74
  75  <refsect1>
  76   <title>Parameters</title>
  77
  78     <variablelist>
  79      <varlistentry id="create-database-name">
  80       <term><replaceable class="parameter">name</replaceable></term>
  81       <listitem>
  82        <para>
  83         The name of a database to create.
  84        </para>
  85       </listitem>
  86      </varlistentry>
  87      <varlistentry id="create-database-user-name">
  88       <term><replaceable class="parameter">user_name</replaceable></term>
  89       <listitem>
  90        <para>
  91         The role name of the user who will own the new database,
  92         or <literal>DEFAULT</literal> to use the default (namely, the
  93         user executing the command).  To create a database owned by another
  94         role, you must be able to <literal>SET ROLE</literal> to that
  95         role.
  96        </para>
  97       </listitem>
  98      </varlistentry>
  99      <varlistentry id="create-database-template">
 100       <term><replaceable class="parameter">template</replaceable></term>
 101       <listitem>
 102        <para>
 103         The name of the template from which to create the new database,
 104         or <literal>DEFAULT</literal> to use the default template
 105         (<literal>template1</literal>).
 106        </para>
 107       </listitem>
 108      </varlistentry>
 109      <varlistentry id="create-database-encoding">
 110       <term><replaceable class="parameter">encoding</replaceable></term>
 111       <listitem>
 112        <para>
 113         Character set encoding to use in the new database.  Specify
 114         a string constant (e.g., <literal>'SQL_ASCII'</literal>),
 115         or an integer encoding number, or <literal>DEFAULT</literal>
 116         to use the default encoding (namely, the encoding of the
 117         template database). The character sets supported by the
 118         <productname>PostgreSQL</productname> server are described in
 119         <xref linkend="multibyte-charset-supported"/>. See below for
 120         additional restrictions.
 121        </para>
 122       </listitem>
 123      </varlistentry>
 124      <varlistentry id="create-database-strategy" xreflabel="CREATE DATABASE STRATEGY">
 125       <term><replaceable class="parameter">strategy</replaceable></term>
 126       <listitem>
 127        <para>
 128         Strategy to be used in creating the new database.  If
 129         the <literal>WAL_LOG</literal> strategy is used, the database will be
 130         copied block by block and each block will be separately written
 131         to the write-ahead log. This is the most efficient strategy in
 132         cases where the template database is small, and therefore it is the
 133         default. The older <literal>FILE_COPY</literal> strategy is also
 134         available. This strategy writes a small record to the write-ahead log
 135         for each tablespace used by the target database. Each such record
 136         represents copying an entire directory to a new location at the
 137         filesystem level. While this does reduce the write-ahead
 138         log volume substantially, especially if the template database is large,
 139         it also forces the system to perform a checkpoint both before and
 140         after the creation of the new database. In some situations, this may
 141         have a noticeable negative impact on overall system performance.
 142        </para>
 143       </listitem>
 144      </varlistentry>
 145      <varlistentry id="create-database-locale">
 146       <term><replaceable class="parameter">locale</replaceable></term>
 147       <listitem>
 148        <para>
 149         Sets the default collation order and character classification in the
 150         new database.  Collation affects the sort order applied to strings,
 151         e.g., in queries with <literal>ORDER BY</literal>, as well as the order used in indexes
 152         on text columns.  Character classification affects the categorization
 153         of characters, e.g., lower, upper, and digit.  Also sets the
 154         associated aspects of the operating system environment,
 155         <literal>LC_COLLATE</literal> and <literal>LC_CTYPE</literal>.  The
 156         default is the same setting as the template database.  See <xref
 157         linkend="collation-managing-create-libc"/> and <xref
 158         linkend="collation-managing-create-icu"/> for details.
 159        </para>
 160        <para>
 161         Can be overridden by setting <xref
 162         linkend="create-database-lc-collate"/>, <xref
 163         linkend="create-database-lc-ctype"/>, <xref
 164         linkend="create-database-builtin-locale"/>, or <xref
 165         linkend="create-database-icu-locale"/> individually.
 166        </para>
 167        <para>
 168         If <xref linkend="create-database-locale-provider"/> is
 169         <literal>builtin</literal>, then <replaceable>locale</replaceable> or
 170         <replaceable>builtin_locale</replaceable> must be specified and set to
 171         either <literal>C</literal>, <literal>C.UTF-8</literal>, or
 172         <literal>PG_UNICODE_FAST</literal>.
 173        </para>
 174        <tip>
 175         <para>
 176          The other locale settings <xref linkend="guc-lc-messages"/>, <xref
 177          linkend="guc-lc-monetary"/>, <xref linkend="guc-lc-numeric"/>, and
 178          <xref linkend="guc-lc-time"/> are not fixed per database and are not
 179          set by this command.  If you want to make them the default for a
 180          specific database, you can use <literal>ALTER DATABASE
 181          ... SET</literal>.
 182         </para>
 183        </tip>
 184       </listitem>
 185      </varlistentry>
 186      <varlistentry id="create-database-lc-collate">
 187       <term><replaceable class="parameter">lc_collate</replaceable></term>
 188       <listitem>
 189        <para>
 190         Sets <literal>LC_COLLATE</literal> in the database server's operating
 191         system environment.  The default is the setting of <xref
 192         linkend="create-database-locale"/> if specified, otherwise the same
 193         setting as the template database.  See below for additional
 194         restrictions.
 195        </para>
 196        <para>
 197         If <xref linkend="create-database-locale-provider"/> is
 198         <literal>libc</literal>, also sets the default collation order to use
 199         in the new database, overriding the setting <xref
 200         linkend="create-database-locale"/>.
 201        </para>
 202       </listitem>
 203      </varlistentry>
 204      <varlistentry id="create-database-lc-ctype">
 205       <term><replaceable class="parameter">lc_ctype</replaceable></term>
 206       <listitem>
 207        <para>
 208         Sets <literal>LC_CTYPE</literal> in the database server's operating
 209         system environment.  The default is the setting of <xref
 210         linkend="create-database-locale"/> if specified, otherwise the same
 211         setting as the template database.  See below for additional
 212         restrictions.
 213        </para>
 214        <para>
 215         If <xref linkend="create-database-locale-provider"/> is
 216         <literal>libc</literal>, also sets the default character
 217         classification to use in the new database, overriding the setting
 218         <xref linkend="create-database-locale"/>.
 219        </para>
 220       </listitem>
 221      </varlistentry>
 222
 223      <varlistentry id="create-database-builtin-locale">
 224       <term><replaceable class="parameter">builtin_locale</replaceable></term>
 225       <listitem>
 226        <para>
 227         Specifies the builtin provider locale for the database default
 228         collation order and character classification, overriding the setting
 229         <xref linkend="create-database-locale"/>.  The <link
 230         linkend="create-database-locale-provider">locale provider</link> must
 231         be <literal>builtin</literal>.  The default is the setting of <xref
 232         linkend="create-database-locale"/> if specified; otherwise the same
 233         setting as the template database.
 234        </para>
 235        <para>
 236         The locales available for the <literal>builtin</literal> provider are
 237         <literal>C</literal>, <literal>C.UTF-8</literal> and
 238         <literal>PG_UNICODE_FAST</literal>.
 239        </para>
 240       </listitem>
 241      </varlistentry>
 242
 243      <varlistentry id="create-database-icu-locale">
 244       <term><replaceable class="parameter">icu_locale</replaceable></term>
 245       <listitem>
 246        <para>
 247         Specifies the ICU locale (see <xref
 248         linkend="collation-managing-create-icu"/>) for the database default
 249         collation order and character classification, overriding the setting
 250         <xref linkend="create-database-locale"/>.  The <link
 251         linkend="create-database-locale-provider">locale provider</link> must be ICU.  The default
 252         is the setting of <xref linkend="create-database-locale"/> if
 253         specified; otherwise the same setting as the template database.
 254        </para>
 255       </listitem>
 256      </varlistentry>
 257
 258      <varlistentry id="create-database-icu-rules">
 259       <term><replaceable class="parameter">icu_rules</replaceable></term>
 260       <listitem>
 261        <para>
 262         Specifies additional collation rules to customize the behavior of the
 263         default collation of this database.  This is supported for ICU only.
 264         See <xref linkend="icu-tailoring-rules"/> for details.
 265        </para>
 266       </listitem>
 267      </varlistentry>
 268
 269      <varlistentry id="create-database-locale-provider">
 270       <term><replaceable>locale_provider</replaceable></term>
 271
 272       <listitem>
 273        <para>
 274         Specifies the provider to use for the default collation in this
 275         database.  Possible values are <literal>builtin</literal>,
 276         <literal>icu</literal><indexterm><primary>ICU</primary></indexterm>
 277         (if the server was built with ICU support) or <literal>libc</literal>.
 278         By default, the provider is the same as that of the <xref
 279         linkend="create-database-template"/>. See <xref
 280         linkend="locale-providers"/> for details.
 281        </para>
 282       </listitem>
 283      </varlistentry>
 284
 285      <varlistentry id="create-database-collation-version">
 286       <term><replaceable>collation_version</replaceable></term>
 287
 288       <listitem>
 289        <para>
 290         Specifies the collation version string to store with the database.
 291         Normally, this should be omitted, which will cause the version to be
 292         computed from the actual version of the database collation as provided
 293         by the operating system.  This option is intended to be used by
 294         <command>pg_upgrade</command> for copying the version from an existing
 295         installation.
 296        </para>
 297
 298        <para>
 299         See also <xref linkend="sql-alterdatabase"/> for how to handle
 300         database collation version mismatches.
 301        </para>
 302      </listitem>
 303     </varlistentry>
 304      <varlistentry id="create-database-tablespace-name">
 305       <term><replaceable class="parameter">tablespace_name</replaceable></term>
 306       <listitem>
 307        <para>
 308         The name of the tablespace that will be associated with the
 309         new database, or <literal>DEFAULT</literal> to use the
 310         template database's tablespace. This
 311         tablespace will be the default tablespace used for objects
 312         created in this database. See
 313         <xref linkend="sql-createtablespace"/>
 314         for more information.
 315        </para>
 316       </listitem>
 317      </varlistentry>
 318
 319       <varlistentry id="create-database-allowconn">
 320        <term><replaceable class="parameter">allowconn</replaceable></term>
 321        <listitem>
 322         <para>
 323          If false then no one can connect to this database.  The default is
 324          true, allowing connections (except as restricted by other mechanisms,
 325          such as <literal>GRANT</literal>/<literal>REVOKE CONNECT</literal>).
 326         </para>
 327        </listitem>
 328       </varlistentry>
 329
 330       <varlistentry id="create-database-connlimit">
 331       <term><replaceable class="parameter">connlimit</replaceable></term>
 332       <listitem>
 333        <para>
 334         How many concurrent connections can be made
 335         to this database.  -1 (the default) means no limit.
 336        </para>
 337       </listitem>
 338      </varlistentry>
 339
 340       <varlistentry id="create-database-istemplate">
 341        <term><replaceable class="parameter">istemplate</replaceable></term>
 342        <listitem>
 343         <para>
 344          If true, then this database can be cloned by any user with <literal>CREATEDB</literal>
 345          privileges; if false (the default), then only superusers or the owner
 346          of the database can clone it.
 347         </para>
 348        </listitem>
 349       </varlistentry>
 350
 351       <varlistentry id="create-database-oid">
 352        <term><replaceable class="parameter">oid</replaceable></term>
 353        <listitem>
 354         <para>
 355          The object identifier to be used for the new database. If this
 356          parameter is not specified, <productname>PostgreSQL</productname>
 357          will choose a suitable OID automatically. This parameter is primarily
 358          intended for internal use by <application>pg_upgrade</application>,
 359          and only <application>pg_upgrade</application> can specify a value
 360          less than 16384.
 361         </para>
 362        </listitem>
 363       </varlistentry>
 364
 365     </variablelist>
 366
 367   <para>
 368    Optional parameters can be written in any order, not only the order
 369    illustrated above.
 370   </para>
 371  </refsect1>
 372
 373  <refsect1>
 374   <title>Notes</title>
 375
 376    <para>
 377     <command>CREATE DATABASE</command> cannot be executed inside a transaction
 378     block.
 379    </para>
 380
 381    <para>
 382     Errors along the line of <quote>could not initialize database directory</quote>
 383     are most likely related to insufficient permissions on the data
 384     directory, a full disk, or other file system problems.
 385    </para>
 386
 387    <para>
 388     Use <link linkend="sql-dropdatabase"><command>DROP DATABASE</command></link> to remove a database.
 389    </para>
 390
 391    <para>
 392     The program <xref linkend="app-createdb"/> is a
 393     wrapper program around this command, provided for convenience.
 394    </para>
 395
 396    <para>
 397     Database-level configuration parameters (set via <link
 398     linkend="sql-alterdatabase"><command>ALTER DATABASE</command></link>) and database-level permissions (set via
 399     <link linkend="sql-grant"><command>GRANT</command></link>) are not copied from the template database.
 400    </para>
 401
 402   <para>
 403    Although it is possible to copy a database other than <literal>template1</literal>
 404    by specifying its name as the template, this is not (yet) intended as
 405    a general-purpose <quote><command>COPY DATABASE</command></quote> facility.
 406    The principal limitation is that no other sessions can be connected to
 407    the template database while it is being copied.  <command>CREATE
 408    DATABASE</command> will fail if any other connection exists when it starts;
 409    otherwise, new connections to the template database are locked out
 410    until <command>CREATE DATABASE</command> completes.
 411    See <xref linkend="manage-ag-templatedbs"/> for more information.
 412   </para>
 413
 414   <para>
 415    The character set encoding specified for the new database must be
 416    compatible with the chosen locale settings (<literal>LC_COLLATE</literal> and
 417    <literal>LC_CTYPE</literal>).  If the locale is <literal>C</literal> (or equivalently
 418    <literal>POSIX</literal>), then all encodings are allowed, but for other
 419    locale settings there is only one encoding that will work properly.
 420    (On Windows, however, UTF-8 encoding can be used with any locale.)
 421    <command>CREATE DATABASE</command> will allow superusers to specify
 422    <literal>SQL_ASCII</literal> encoding regardless of the locale settings,
 423    but this choice is deprecated and may result in misbehavior of
 424    character-string functions if data that is not encoding-compatible
 425    with the locale is stored in the database.
 426   </para>
 427
 428   <para>
 429    The encoding and locale settings must match those of the template database,
 430    except when <literal>template0</literal> is used as template.  This is because
 431    other databases might contain data that does not match the specified
 432    encoding, or might contain indexes whose sort ordering is affected by
 433    <literal>LC_COLLATE</literal> and <literal>LC_CTYPE</literal>.  Copying such data would
 434    result in a database that is corrupt according to the new settings.
 435    <literal>template0</literal>, however, is known to not contain any data or
 436    indexes that would be affected.
 437   </para>
 438
 439   <para>
 440    There is currently no option to use a database locale with nondeterministic
 441    comparisons (see <link linkend="sql-createcollation"><command>CREATE
 442    COLLATION</command></link> for an explanation).  If this is needed, then
 443    per-column collations would need to be used.
 444   </para>
 445
 446   <para>
 447    The <literal>CONNECTION LIMIT</literal> option is only enforced approximately;
 448    if two new sessions start at about the same time when just one
 449    connection <quote>slot</quote> remains for the database, it is possible that
 450    both will fail.  Also, the limit is not enforced against superusers or
 451    background worker processes.
 452   </para>
 453  </refsect1>
 454
 455  <refsect1>
 456   <title>Examples</title>
 457
 458   <para>
 459    To create a new database:
 460
 461 <programlisting>
 462 CREATE DATABASE lusiadas;
 463 </programlisting>
 464   </para>
 465
 466   <para>
 467    To create a database <literal>sales</literal> owned by user <literal>salesapp</literal>
 468    with a default tablespace of <literal>salesspace</literal>:
 469
 470 <programlisting>
 471 CREATE DATABASE sales OWNER salesapp TABLESPACE salesspace;
 472 </programlisting>
 473   </para>
 474
 475   <para>
 476    To create a database <literal>music</literal> with a different locale:
 477 <programlisting>
 478 CREATE DATABASE music
 479     LOCALE 'sv_SE.utf8'
 480     TEMPLATE template0;
 481 </programlisting>
 482     In this example, the <literal>TEMPLATE template0</literal> clause is required if
 483     the specified locale is different from the one in <literal>template1</literal>.
 484     (If it is not, then specifying the locale explicitly is redundant.)
 485   </para>
 486
 487   <para>
 488    To create a database <literal>music2</literal> with a different locale and a
 489    different character set encoding:
 490 <programlisting>
 491 CREATE DATABASE music2
 492     LOCALE 'sv_SE.iso885915'
 493     ENCODING LATIN9
 494     TEMPLATE template0;
 495 </programlisting>
 496    The specified locale and encoding settings must match, or an error will be
 497    reported.
 498   </para>
 499
 500   <para>
 501    Note that locale names are specific to the operating system, so that the
 502    above commands might not work in the same way everywhere.
 503   </para>
 504  </refsect1>
 505
 506  <refsect1>
 507   <title>Compatibility</title>
 508
 509   <para>
 510    There is no <command>CREATE DATABASE</command> statement in the SQL
 511    standard.  Databases are equivalent to catalogs, whose creation is
 512    implementation-defined.
 513   </para>
 514  </refsect1>
 515
 516  <refsect1>
 517   <title>See Also</title>
 518
 519   <simplelist type="inline">
 520    <member><xref linkend="sql-alterdatabase"/></member>
 521    <member><xref linkend="sql-dropdatabase"/></member>
 522   </simplelist>
 523  </refsect1>
 524
 525 </refentry>