mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-24 08:32:02 +00:00
134 lines
3.9 KiB
Markdown
134 lines
3.9 KiB
Markdown
---
|
|
slug: /en/sql-reference/statements/create/dictionary
|
|
sidebar_position: 38
|
|
sidebar_label: DICTIONARY
|
|
title: "CREATE DICTIONARY"
|
|
---
|
|
|
|
Creates a new [dictionary](../../../sql-reference/dictionaries/index.md) with given [structure](../../../sql-reference/dictionaries/index.md#dictionary-key-and-fields), [source](../../../sql-reference/dictionaries/index.md#dictionary-sources), [layout](../../../sql-reference/dictionaries/index.md#storig-dictionaries-in-memory) and [lifetime](../../../sql-reference/dictionaries/index.md#dictionary-updates).
|
|
|
|
## Syntax
|
|
|
|
``` sql
|
|
CREATE [OR REPLACE] DICTIONARY [IF NOT EXISTS] [db.]dictionary_name [ON CLUSTER cluster]
|
|
(
|
|
key1 type1 [DEFAULT|EXPRESSION expr1] [IS_OBJECT_ID],
|
|
key2 type2 [DEFAULT|EXPRESSION expr2],
|
|
attr1 type2 [DEFAULT|EXPRESSION expr3] [HIERARCHICAL|INJECTIVE],
|
|
attr2 type2 [DEFAULT|EXPRESSION expr4] [HIERARCHICAL|INJECTIVE]
|
|
)
|
|
PRIMARY KEY key1, key2
|
|
SOURCE(SOURCE_NAME([param1 value1 ... paramN valueN]))
|
|
LAYOUT(LAYOUT_NAME([param_name param_value]))
|
|
LIFETIME({MIN min_val MAX max_val | max_val})
|
|
SETTINGS(setting_name = setting_value, setting_name = setting_value, ...)
|
|
COMMENT 'Comment'
|
|
```
|
|
|
|
The dictionary structure consists of attributes. Dictionary attributes are specified similarly to table columns. The only required attribute property is its type, all other properties may have default values.
|
|
|
|
`ON CLUSTER` clause allows creating dictionary on a cluster, see [Distributed DDL](../../../sql-reference/distributed-ddl.md).
|
|
|
|
Depending on dictionary [layout](../../../sql-reference/dictionaries/index.md#storig-dictionaries-in-memory) one or more attributes can be specified as dictionary keys.
|
|
|
|
## SOURCE
|
|
|
|
The source for a dictionary can be a:
|
|
- table in the current ClickHouse service
|
|
- table in a remote ClickHouse service
|
|
- file available by HTTP(S)
|
|
- another database
|
|
|
|
### Create a dictionary from a table in the current ClickHouse service
|
|
|
|
Input table `source_table`:
|
|
|
|
``` text
|
|
┌─id─┬─value──┐
|
|
│ 1 │ First │
|
|
│ 2 │ Second │
|
|
└────┴────────┘
|
|
```
|
|
|
|
Creating the dictionary:
|
|
|
|
``` sql
|
|
CREATE DICTIONARY id_value_dictionary
|
|
(
|
|
id UInt64,
|
|
value String
|
|
)
|
|
PRIMARY KEY id
|
|
SOURCE(CLICKHOUSE(TABLE 'source_table'))
|
|
LAYOUT(FLAT())
|
|
LIFETIME(MIN 0 MAX 1000)
|
|
```
|
|
|
|
Output the dictionary:
|
|
|
|
``` sql
|
|
SHOW CREATE DICTIONARY id_value_dictionary;
|
|
```
|
|
|
|
```response
|
|
CREATE DICTIONARY default.id_value_dictionary
|
|
(
|
|
`id` UInt64,
|
|
`value` String
|
|
)
|
|
PRIMARY KEY id
|
|
SOURCE(CLICKHOUSE(TABLE 'source_table'))
|
|
LIFETIME(MIN 0 MAX 1000)
|
|
LAYOUT(FLAT())
|
|
```
|
|
|
|
### Create a dictionary from a table in a remote ClickHouse service
|
|
|
|
Input table (in the remote ClickHouse service) `source_table`:
|
|
|
|
``` text
|
|
┌─id─┬─value──┐
|
|
│ 1 │ First │
|
|
│ 2 │ Second │
|
|
└────┴────────┘
|
|
```
|
|
|
|
Creating the dictionary:
|
|
|
|
``` sql
|
|
CREATE DICTIONARY id_value_dictionary
|
|
(
|
|
id UInt64,
|
|
value String
|
|
)
|
|
PRIMARY KEY id
|
|
SOURCE(CLICKHOUSE(HOST 'HOSTNAME' PORT 9000 USER 'default' PASSWORD 'PASSWORD' TABLE 'source_table' DB 'default'))
|
|
LAYOUT(FLAT())
|
|
LIFETIME(MIN 0 MAX 1000)
|
|
```
|
|
|
|
### Create a dictionary from a file available by HTTP(S)
|
|
|
|
```sql
|
|
CREATE DICTIONARY default.taxi_zone_dictionary
|
|
(
|
|
`LocationID` UInt16 DEFAULT 0,
|
|
`Borough` String,
|
|
`Zone` String,
|
|
`service_zone` String
|
|
)
|
|
PRIMARY KEY LocationID
|
|
SOURCE(HTTP(URL 'https://datasets-documentation.s3.eu-west-3.amazonaws.com/nyc-taxi/taxi_zone_lookup.csv' FORMAT 'CSVWithNames'))
|
|
LIFETIME(MIN 0 MAX 0)
|
|
LAYOUT(HASHED())
|
|
```
|
|
|
|
### Create a dictionary from another database
|
|
|
|
Please see the details in [Dictionary sources](/docs/en/sql-reference/dictionaries/index.md#dictionary-sources/#dbms).
|
|
|
|
**See Also**
|
|
|
|
- For more information, see the [Dictionaries](../../../sql-reference/dictionaries/index.md) section.
|
|
- [system.dictionaries](../../../operations/system-tables/dictionaries.md) — This table contains information about [Dictionaries](../../../sql-reference/dictionaries/index.md).
|