Github user dyozie commented on a diff in the pull request:
https://github.com/apache/incubator-hawq-docs/pull/86#discussion_r96318306
--- Diff: markdown/ddl/ddl-database.html.md.erb ---
@@ -2,77 +2,75 @@
title: Creating and Managing Databases
---
-A HAWQ system is a single instance of HAWQ. There can be several separate
HAWQ systems installed, but usually just one is selected by environment
variable settings. See your HAWQ administrator for details.
-
-There can be multiple databases in a HAWQ system. This is different from
some database management systems \(such as Oracle\) where the database instance
*is* the database. Although you can create many databases in a HAWQ system,
client programs can connect to and access only one database at a time â you
cannot cross-query between databases.
+Your HAWQ deployment may have multiple databases. This is different from
some database management systems \(such as Oracle\) where the database instance
*is* the database. Although you can create many databases in a HAWQ system,
client programs can connect to and access only one database at a time â you
cannot cross-query between databases.
## <a id="topic3"></a>About Template Databases
-Each new database you create is based on a *template*. HAWQ provides a
default database, *template1*. Use *template1* to connect to HAWQ for the first
time. HAWQ uses *template1* to create databases unless you specify another
template. Do not create any objects in *template1* unless you want those
objects to be in every database you create.
+Each new database you create is based on a *template*. HAWQ provides a
default database, `template1`. HAWQ uses `template1` to create databases unless
you specify another template. Do not create any objects in `template1` unless
you want those objects to be in every database you create.
-HAWQ uses two other database templates, *template0* and *postgres*,
internally. Do not drop or modify *template0* or *postgres*. You can use
*template0* to create a completely clean database containing only the standard
objects predefined by HAWQ at initialization, especially if you modified
*template1*.
+HAWQ uses two other database templates internally, `template0` and
`postgres`. Do not drop or modify `template0` or `postgres`. You can use
`template0` to create a completely clean database containing only the standard
objects predefined by HAWQ at initialization, especially if you have modified
`template1`.
## <a id="topic4"></a>Creating a Database
-The `CREATE DATABASE` command creates a new database. For example:
+You must have appropriate privileges or be a HAWQ superuser to create a
database. If you do not have the correct privileges, you cannot create a
database. The HAWQ administrator must either grant you the necessary privileges
or create a database for you.
+
+The [CREATE DATABASE](../reference/sql/CREATE-DATABASE.html) command
creates a new database. For example:
``` sql
-=> CREATE DATABASE new_dbname;
+=# CREATE DATABASE <new_dbname>;
```
-To create a database, you must have privileges to create a database or be
a HAWQ superuser. If you do not have the correct privileges, you cannot create
a database. The HAWQ administrator must either give you the necessary
privileges or to create a database for you.
-
-You can also use the client program `createdb` to create a database. For
example, running the following command in a command line terminal connects to
HAWQ using the provided host name and port and creates a database named
*mydatabase*:
+You can also use the client program `createdb` to create a database. For
example, running the following command connects to HAWQ on the host named
`hmaster` at port `5432` and creates a database named `mydatabase`:
``` shell
-$ createdb -h masterhost -p 5432 mydatabase
+$ createdb -h hmaster -p 5432 mydatabase
```
-The host name and port must match the host name and port of the installed
HAWQ system.
+The host name and port must match the host name and port of the HAWQ
master node.
-Some objects, such as roles, are shared by all the databases in a HAWQ
system. Other objects, such as tables that you create, are known only in the
database in which you create them.
+Some objects, such as roles, are shared by all of the databases in a HAWQ
deployment. Other objects, such as tables that you create, are known only to
the database in which you create them.
### <a id="topic5"></a>Cloning a Database
-By default, a new database is created by cloning the standard system
database template, *template1*. Any database can be used as a template when
creating a new database, thereby providing the capability to 'clone' or copy an
existing database and all objects and data within that database. For example:
+By default, a new database is created by cloning the standard system
database template, `template1`. You may identify an alternate template to use
for database creation. As mentioned in the section above, you can specify
`template0` as the template:
``` sql
-=> CREATE DATABASE new_dbname TEMPLATE old_dbname
+=# CREATE DATABASE <new_dbname> WITH TEMPLATE template0;
```
## <a id="topic6"></a>Viewing the List of Databases
-If you are working in the `psql` client program, you can use the `\l`
meta-command to show the list of databases and templates in your HAWQ system.
If using another client program and you are a superuser, you can query the list
of databases from the `pg_database` system catalog table. For example:
+You can use the `\l` meta-command of the `psql` client subsystem to
display the list of databases and templates in your HAWQ deployment. If you are
a database superuser, you can query the list of databases from the
`pg_database` system catalog table. For example:
``` sql
-=> SELECT datname FROM pg_database;
+=# SELECT datname FROM pg_database;
```
## <a id="topic7"></a>Altering a Database
-The ALTER DATABASE command changes database attributes such as owner,
name, or default configuration attributes. For example, the following command
alters a database by setting its default schema search path \(the `search_path`
configuration parameter\):
+Use the [ALTER DATABASE](../reference/sql/ALTER-DATABASE.html) command to
update database attributes including owner or name. You can also use ALTER
DATABASE to update a database's default configuration. For example, the
following command alters a database by setting its default schema search path
using the `search_path` server configuration parameter:
``` sql
-=> ALTER DATABASE mydatabase SET search_path TO myschema, public,
pg_catalog;
+=# ALTER DATABASE mydatabase SET search_path TO myschema, public,
pg_catalog;
```
To alter a database, you must be the owner of the database or a superuser.
## <a id="topic8"></a>Dropping a Database
-The `DROP DATABASE` command drops \(or deletes\) a database. It removes
the system catalog entries for the database and deletes the database directory
on disk that contains the data. You must be the database owner or a superuser
to drop a database, and you cannot drop a database while you or anyone else is
connected to it. Connect to `template1` \(or another database\) before dropping
a database. For example:
+The [DROP DATABASE](../reference/sql/DROP-DATABASE.html) command drops
\(or deletes\) a database. It removes the system catalog entries for the
database and deletes the data on disk. You must be the database owner or a
superuser to drop a database, and you cannot drop a database while you or
anyone else is connected to it. Connect to `template1` \(or another database\)
before dropping a database. For example:
--- End diff --
(or deletes) -> (deletes)
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