2019-08-19 02:17:50 -04:00
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---
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layout: global
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title: DROP DATABASE
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displayTitle: DROP DATABASE
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license: |
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Licensed to the Apache Software Foundation (ASF) under one or more
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contributor license agreements. See the NOTICE file distributed with
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this work for additional information regarding copyright ownership.
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The ASF licenses this file to You under the Apache License, Version 2.0
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(the "License"); you may not use this file except in compliance with
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the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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---
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2019-09-13 02:10:50 -04:00
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### Description
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Drop a database and delete the directory associated with the database from the file system. An
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exception will be thrown if the database does not exist in the system.
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### Syntax
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2020-05-10 13:57:25 -04:00
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```sql
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2020-04-30 17:30:35 -04:00
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DROP { DATABASE | SCHEMA } [ IF EXISTS ] dbname [ RESTRICT | CASCADE ]
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2020-05-10 13:57:25 -04:00
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```
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2019-09-13 02:10:50 -04:00
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### Parameters
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2020-05-10 13:57:25 -04:00
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* **DATABASE `|` SCHEMA**
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2019-09-13 02:10:50 -04:00
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2020-05-10 13:57:25 -04:00
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`DATABASE` and `SCHEMA` mean the same thing, either of them can be used.
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2019-09-13 02:10:50 -04:00
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2020-05-10 13:57:25 -04:00
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* **IF EXISTS**
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2019-09-13 02:10:50 -04:00
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2020-05-10 13:57:25 -04:00
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If specified, no exception is thrown when the database does not exist.
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* **RESTRICT**
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If specified, will restrict dropping a non-empty database and is enabled by default.
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* **CASCADE**
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If specified, will drop all the associated tables and functions.
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2019-09-13 02:10:50 -04:00
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2020-04-30 17:30:35 -04:00
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### Examples
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[SPARK-31383][SQL][DOC] Clean up the SQL documents in docs/sql-ref*
### What changes were proposed in this pull request?
This PR intends to clean up the SQL documents in `doc/sql-ref*`.
Main changes are as follows;
- Fixes wrong syntaxes and capitalize sub-titles
- Adds some DDL queries in `Examples` so that users can run examples there
- Makes query output in `Examples` follows the `Dataset.showString` (right-aligned) format
- Adds/Removes spaces, Indents, or blank lines to follow the format below;
```
---
license...
---
### Description
Writes what's the syntax is.
### Syntax
{% highlight sql %}
SELECT...
WHERE... // 4 indents after the second line
...
{% endhighlight %}
### Parameters
<dl>
<dt><code><em>Param Name</em></code></dt>
<dd>
Param Description
</dd>
...
</dl>
### Examples
{% highlight sql %}
-- It is better that users are able to execute example queries here.
-- So, we prepare test data in the first section if possible.
CREATE TABLE t (key STRING, value DOUBLE);
INSERT INTO t VALUES
('a', 1.0), ('a', 2.0), ('b', 3.0), ('c', 4.0);
-- query output has 2 indents and it follows the `Dataset.showString`
-- format (right-aligned).
SELECT * FROM t;
+---+-----+
|key|value|
+---+-----+
| a| 1.0|
| a| 2.0|
| b| 3.0|
| c| 4.0|
+---+-----+
-- Query statements after the second line have 4 indents.
SELECT key, SUM(value)
FROM t
GROUP BY key;
+---+----------+
|key|sum(value)|
+---+----------+
| c| 4.0|
| b| 3.0|
| a| 3.0|
+---+----------+
...
{% endhighlight %}
### Related Statements
* [XXX](xxx.html)
* ...
```
### Why are the changes needed?
The most changes of this PR are pretty minor, but I think the consistent formats/rules to write documents are important for long-term maintenance in our community
### Does this PR introduce any user-facing change?
Yes.
### How was this patch tested?
Manually checked.
Closes #28151 from maropu/MakeRightAligned.
Authored-by: Takeshi Yamamuro <yamamuro@apache.org>
Signed-off-by: Sean Owen <srowen@gmail.com>
2020-04-13 00:40:36 -04:00
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2020-05-10 13:57:25 -04:00
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```sql
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2019-09-13 02:10:50 -04:00
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-- Create `inventory_db` Database
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CREATE DATABASE inventory_db COMMENT 'This database is used to maintain Inventory';
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-- Drop the database and it's tables
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DROP DATABASE inventory_db CASCADE;
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-- Drop the database using IF EXISTS
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DROP DATABASE IF EXISTS inventory_db CASCADE;
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2020-05-10 13:57:25 -04:00
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```
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2019-09-13 02:10:50 -04:00
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|
[SPARK-31383][SQL][DOC] Clean up the SQL documents in docs/sql-ref*
### What changes were proposed in this pull request?
This PR intends to clean up the SQL documents in `doc/sql-ref*`.
Main changes are as follows;
- Fixes wrong syntaxes and capitalize sub-titles
- Adds some DDL queries in `Examples` so that users can run examples there
- Makes query output in `Examples` follows the `Dataset.showString` (right-aligned) format
- Adds/Removes spaces, Indents, or blank lines to follow the format below;
```
---
license...
---
### Description
Writes what's the syntax is.
### Syntax
{% highlight sql %}
SELECT...
WHERE... // 4 indents after the second line
...
{% endhighlight %}
### Parameters
<dl>
<dt><code><em>Param Name</em></code></dt>
<dd>
Param Description
</dd>
...
</dl>
### Examples
{% highlight sql %}
-- It is better that users are able to execute example queries here.
-- So, we prepare test data in the first section if possible.
CREATE TABLE t (key STRING, value DOUBLE);
INSERT INTO t VALUES
('a', 1.0), ('a', 2.0), ('b', 3.0), ('c', 4.0);
-- query output has 2 indents and it follows the `Dataset.showString`
-- format (right-aligned).
SELECT * FROM t;
+---+-----+
|key|value|
+---+-----+
| a| 1.0|
| a| 2.0|
| b| 3.0|
| c| 4.0|
+---+-----+
-- Query statements after the second line have 4 indents.
SELECT key, SUM(value)
FROM t
GROUP BY key;
+---+----------+
|key|sum(value)|
+---+----------+
| c| 4.0|
| b| 3.0|
| a| 3.0|
+---+----------+
...
{% endhighlight %}
### Related Statements
* [XXX](xxx.html)
* ...
```
### Why are the changes needed?
The most changes of this PR are pretty minor, but I think the consistent formats/rules to write documents are important for long-term maintenance in our community
### Does this PR introduce any user-facing change?
Yes.
### How was this patch tested?
Manually checked.
Closes #28151 from maropu/MakeRightAligned.
Authored-by: Takeshi Yamamuro <yamamuro@apache.org>
Signed-off-by: Sean Owen <srowen@gmail.com>
2020-04-13 00:40:36 -04:00
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### Related Statements
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2020-05-10 13:57:25 -04:00
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* [CREATE DATABASE](sql-ref-syntax-ddl-create-database.html)
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* [DESCRIBE DATABASE](sql-ref-syntax-aux-describe-database.html)
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* [SHOW DATABASES](sql-ref-syntax-aux-show-databases.html)
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