> ## Documentation Index
> Fetch the complete documentation index at: https://private-7c7dfe99-fix-nav-issues.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

> ClickHouse R2DBC driver

# R2DBC driver

<h2 id="r2dbc-driver">
  R2DBC driver
</h2>

[R2DBC](https://r2dbc.io/) wrapper of async Java client for ClickHouse.

<h3 id="environment-requirements">
  Environment requirements
</h3>

* [OpenJDK](https://openjdk.java.net) version >= 8

<h3 id="setup">
  Setup
</h3>

```xml theme={null}
<dependency>
    <groupId>com.clickhouse</groupId>
    <!-- change to clickhouse-r2dbc_0.9.1 for SPI 0.9.1.RELEASE -->
    <artifactId>clickhouse-r2dbc</artifactId>
    <version>0.7.1</version>
    <!-- use uber jar with all dependencies included, change classifier to http or grpc for smaller jar -->
    <classifier>all</classifier>
    <exclusions>
        <exclusion>
            <groupId>*</groupId>
            <artifactId>*</artifactId>
        </exclusion>
    </exclusions>
</dependency>
```

<h3 id="connect-to-clickhouse">
  Connect to ClickHouse
</h3>

```java showLineNumbers theme={null}
ConnectionFactory connectionFactory = ConnectionFactories
    .get("r2dbc:clickhouse:http://{username}:{password}@{host}:{port}/{database}");

    Mono.from(connectionFactory.create())
        .flatMapMany(connection -> connection
```

<h3 id="query">
  Query
</h3>

```java showLineNumbers theme={null}
connection
    .createStatement("select domain, path,  toDate(cdate) as d, count(1) as count from clickdb.clicks where domain = :domain group by domain, path, d")
    .bind("domain", domain)
    .execute()
    .flatMap(result -> result
    .map((row, rowMetadata) -> String.format("%s%s[%s]:%d", row.get("domain", String.class),
        row.get("path", String.class),
        row.get("d", LocalDate.class),
        row.get("count", Long.class)))
    )
    .doOnNext(System.out::println)
    .subscribe();
```

<h3 id="insert">
  Insert
</h3>

```java showLineNumbers theme={null}
connection
    .createStatement("insert into clickdb.clicks values (:domain, :path, :cdate, :count)")
    .bind("domain", click.getDomain())
    .bind("path", click.getPath())
    .bind("cdate", LocalDateTime.now())
    .bind("count", 1)
    .execute();
```