markdown/reference/sql/ALTER-DATABASE.html.md.erb

---
title: ALTER DATABASE
---

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Changes the attributes of a database.

## <a id="alterrole__section2"></a>Synopsis

```pre
ALTER DATABASE <name> SET <parameter> { TO | = } { <value> | DEFAULT } 

ALTER DATABASE <name> RESET <parameter>
```

## <a id="desc"></a>Description

`ALTER DATABASE` changes the attributes of a HAWQ database.

`SET` and `RESET` \<parameter\> changes the session default for a configuration parameter for a HAWQ database. Whenever a new session is subsequently started in that database, the specified value becomes the session default value. The database-specific default overrides whatever setting is present in the server configuration file (`hawq-site.xml`). Only the database owner or a superuser can change the session defaults for a database. Certain parameters cannot be set this way, or can only be set by a superuser.

## <a id="alterrole__section4"></a>Parameters

<dt> \<name\>   </dt>
<dd>The name of the database whose attributes are to be altered.

**Note:** HAWQ reserves the database "hcatalog" for system use. You cannot connect to or alter the system "hcatalog" database.</dd>

<dt> \<parameter\>   </dt>
<dd>Set this database's session default for the specified configuration parameter to the given value. If value is `DEFAULT` or if `RESET` is used, the database-specific setting is removed, so the system-wide default setting will be inherited in new sessions. Use `RESET ALL` to clear all database-specific settings. See [About Server Configuration Parameters](../guc/guc_config.html#topic1) for information about user-settable configuration parameters.</dd>

## <a id="notes"></a>Notes

It is also possible to set a configuration parameter session default for a specific role (user) rather than to a database. Role-specific settings override database-specific ones if there is a conflict. See [ALTER ROLE](ALTER-ROLE.html).

## <a id="examples"></a>Examples

To set the default schema search path for the `mydatabase` database:

```pre
ALTER DATABASE mydatabase SET search_path TO myschema, 
public, pg_catalog;
```

## <a id="compat"></a>Compatibility

The `ALTER DATABASE` statement is a HAWQ extension.

## <a id="see"></a>See Also

[CREATE DATABASE](CREATE-DATABASE.html#topic1), [DROP DATABASE](DROP-DATABASE.html#topic1), [SET](SET.html)