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