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> Use this file to discover all available pages before exploring further.

# How to Create a ClickHouse Dictionary with String Keys and Values

> Learn how to create a ClickHouse dictionary using string keys and values from a MergeTree table as the source, with examples of setup and usage.

## Question

How to create a ClickHouse dictionary using string keys and string values from a MergeTree table source

## Answer

* Create the source table for the dictionary

```
CREATE TABLE db1.table1_dict_source
(
  id UInt32,
  email String,
  name String
)
ENGINE = MergeTree()
ORDER BY id;
```

* Insert rows

```
INSERT INTO db1.table1_dict_source
(id, email, name)
VALUES
(1, 'me@domain.com', 'me'),
(2, 'you@domain.com', 'you');
```

* Create  dictionary with key/value both as String

```
CREATE DICTIONARY db1.table1_dict
(
    email String,
    name String
)
PRIMARY KEY email
SOURCE(
CLICKHOUSE(
TABLE 'table1_dict_source'
USER 'default'
PASSWORD 'ClickHouse123!'))
LAYOUT(COMPLEX_KEY_HASHED())
LIFETIME(MIN 0 MAX 1000);
```

* Test the dictionary

```
clickhouse-cloud :) SELECT * from db1.table1_dict;

SELECT *
FROM db1.table1_dict

Query id: 098396ce-11dd-4c71-a0e1-40723dd67ddc

┌─email──────────┬─name─┐
│ me@domain.com  │ me   │
│ you@domain.com │ you  │
└────────────────┴──────┘

2 rows in set. Elapsed: 0.001 sec. 
```

You can also use dictGet function to retrieve values from it such as:

```
SELECT dictGet('db1.table1_dict', 'name', 'me@domain.com');
```

Response:

```
┌─dictGet('db1.table1_dict', 'name', 'me@domain.com')─┐
│ me                                                  │
└─────────────────────────────────────────────────────┘
```

More details - [https://clickhouse.com/docs/sql-reference/functions/ext-dict-functions](https://clickhouse.com/docs/sql-reference/functions/ext-dict-functions)