注意
只有超级用户或具有特殊的CREATEDB特权才可以创建数据库。
默认情况下，可通过克隆标准系统数据库template1创建新数据库。
可通过写TEMPLATE name指定不同的模板。
可通过写TEMPLATE template0您可以创建一个干净的数据库，只包含Teledb所预定义的标准对象。

以下为创建数据库相关操作。

• 默认参数创建数据库

  teledb=# create database teledb_db;
  CREATE DATABASE
  

• 指定克隆库

  teledb=# create database teledb_db_template TEMPLATE  template0;
  CREATE DATABASE
  

• 指定所有者

  teledb=# create role teledb_user with login;
  CREATE ROLE
  teledb=# create database teledb_db_owner owner teledb_user;
  CREATE DATABASE
  teledb=# \l+ teledb_db_owner 
                                                         List of databases
         Name       |    Owner     | Encoding |   Collate   |    Ctype    | Access privileges | Size  | Tablespace | Description 
  ------------------+--------------+----------+-------------+-------------+-------------------+-------+------------+-------------
   teledb_db_owner | teledb_user | UTF8     | zh_CN.UTF-8 | zh_CN.UTF-8 |                   | 19 MB | pg_default | 
  (1 row)
  

• 指定编码

  teledb=# create database teledb_db_encoding ENCODING UTF8;  
  CREATE DATABASE
  teledb=# \l+ teledb_db_encoding 
                                                        List of databases
          Name         |  Owner  | Encoding |   Collate   |    Ctype    | Access privileges | Size  | Tablespace | Description 
  ---------------------+---------+----------+-------------+-------------+-------------------+-------+------------+-------------
   teledb_db_encoding | teledb | UTF8     | zh_CN.UTF-8 | zh_CN.UTF-8 |                   | 19 MB | pg_default | 
  (1 row)
  

• 创建gbk编码

  teledb=# CREATE DATABASE db_gbk template template0 encoding = gbk LC_COLLATE = 'zh_CN.gbk' LC_CTYPE = 'zh_CN.gbk';
  CREATE DATABASE
  teledb=# \d db_gbk
  Did not find any relation named "db_gbk".
  teledb=# \l+ db_gbk
                                               List of databases
    Name  |  Owner  | Encoding |  Collate  |   Ctype   | Access privileges | Size  | Tablespace | Description 
  --------+---------+----------+-----------+-----------+-------------------+-------+------------+-------------
   db_gbk | teledb | GBK      | zh_CN.gbk | zh_CN.gbk |                   | 19 MB | pg_default | 
  (1 row)
  

• 指定排序规则

  teledb=# create database teledb_db_lc_collate lc_collate 'C' template template0;
  CREATE DATABASE
  

• 指定分组规则

  teledb=# create database teledb_lc_ctype LC_CTYPE 'C' template template0;
  CREATE DATABASE
  

• 配置数据可连接

  teledb=# create database teledb__allow_connections ALLOW_CONNECTIONS true;
  CREATE DATABASE
  teledb=# select datallowconn from pg_database where datname = 'teledb__allow_connections';
   datallowconn 
  --------------
   t
  (1 row)
  teledb=# \c teledb__allow_connections
  You are now connected to database "teledb__allow_connections" as user "teledb".
  

• 配置连接数

  teledb=# create database teledb_connlimit CONNECTION LIMIT 100;
  CREATE DATABASE
  teledb=# select datconnlimit  from pg_database where datname='teledb_connlimit';  
   datconnlimit 
  --------------
            100
  (1 row)
  

• 配置数据库可以被复制（是否模板数据库）

  teledb=#  create database teledb_istemplate is_template true;
  CREATE DATABASE
  teledb=# select datconnlimit  from pg_database where datname='teledb_connlimit';  
   datconnlimit 
  --------------
            100
  (1 row)
  

• 同时配置多个参数

  teledb=# create database teledb_mul owner teledb_user  CONNECTION LIMIT 50 template template0 encoding 'utf8'  lc_collate 'C';
  CREATE DATABASE