---
id: clickhouse
title: ClickHouse
---
ToolJet can connect to the ClickHouse to read and write data.
:::info
ToolJet uses this [NodeJS](https://github.com/TimonKK/clickhouse) client for ClickHouse.
:::
## Connection
To establish a connection with the Clickhouse data source, you can either click on the **+ Add new data source** button located on the query panel or navigate to the **[Data Sources](/docs/data-sources/overview)** page through the ToolJet dashboard.
ToolJet requires the following to connect to your ClickHouse Database:
- **Username**
- **Password**
- **Host**
- **Port**
- **Database Name**
- **Protocol**
- **Use Post**
- **Trim Query**
- **Use Gzip**
- **Debug**
- **Raw**
#### CREATE:
```sql
CREATE TABLE test array3 (
date Date,
str String,
arr Array(String),
arr2 Array (Date)
arr3 Array(UInt32) ,
id1 UUID
)ENGINE=MergeTree () ORDER BY(str)
```
#### ALTER TABLE (add column)
```sql
ALTER TABLE test array1 ADD COLUMN Added2 UInt32;
```
#### SELECT WITH WHERE CLAUSE
```sql
SELECT * FROM test array1 WHERE str='Somethingl...'
```
#### UPDATE
```sql
ALTER TABLE test_array1 UPDATE arr = (12] WHERE str='Somethingl...'
```
#### DELETE
```sql
ALTER TABLE test_array1 DELETE WHERE str= 'Somethingl...'
```
#### NORMAL INSERT
##### Step 1 - Creating Table
```sql
CREATE TABLE test array4 (
name String,
date Date
)ENGINE=MergeTree () ORDER BY (name)
```
#### Step 2 - Insert
```sql
INSERT INTO test_array4 (*) VALUES ('juvane', '1996-01-13')
```
:::info
**Giving Primary Key**
```sql
CREATE TABLE db.table_name
(
name1 type1, name2 type2, ...,
PRIMARY KEY(expr1[, expr2,...])]
)
ENGINE = engine;
OR
CREATE TABLE db.table_name
(
name1 type1, name2 type2, ...
)
ENGINE = engine
PRIMARY KEY(expr1[, expr2,...]);
```
:::
### Insert Array of Objects
Use this operation for inserting array of objects.
#### Required Parameters:
- **Body**
- **Table name**
- **Fields**
**Example Body value:**
```javascript
[
{ "id": 1, "name": "Alice", "age": 25 },
{ "id": 2, "name": "Bob", "age": 30 },
{ "id": 3, "name": "Charlie", "age": 28 }
]
```