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GreptimeDB uses different client libraries for writing and querying data. You can choose the client library that best suits your needs.

Write data​

GreptimeDB provides an ingester library to help you write data. It utilizes the gRPC protocol, which supports schemaless writing and eliminates the need to create tables before writing data. For more information, refer to Automatic Schema Generation.

{template ingester-lib-introduction%%}

Installation​

{template ingester-lib-installation%%}

Connect to database​

Username and password are always required to connect to GreptimeDB. For how to set authentication to GreptimeDB, see Authentication. Here we set the username and password when using the library to connect to GreptimeDB.

{template ingester-lib-connect%%}

Data model​

Each row item in a table consists of three types of columns: Tag, Timestamp, and Field. For more information, see Data Model. The types of column values could be String, Float, Int, Timestamp, etc. For more information, see Data Types.

Low-level API​

The GreptimeDB low-level API provides a straightforward method to write data to GreptimeDB by adding rows to the table object with a predefined schema.

Create row objects​

This following code snippet begins by constructing a table named cpu_metric, which includes columns host, cpu_user, cpu_sys, and ts. Subsequently, it inserts a single row into the table.

The table consists of three types of columns:

  • Tag: The host column, with values of type String.
  • Field: The cpu_user and cpu_sys columns, with values of type Float.
  • Timestamp: The ts column, with values of type Timestamp.

{template low-level-object%%}

To improve the efficiency of writing data, you can create multiple rows at once to write to GreptimeDB.

{template create-rows%%}

Insert data​

The following example shows how to insert rows to tables in GreptimeDB.

{template insert-rows%%}

Streaming insert​

Streaming insert is useful when you want to insert a large amount of data such as importing historical data.

{template streaming-insert%%}

{template update-rows%%}

High-level API​

The high-level API uses an ORM style object to write data to GreptimeDB. It allows you to create, insert, and update data in a more object-oriented way, providing developers with a friendlier experience. However, it is not as efficient as the low-level API. This is because the ORM style object may consume more resources and time when converting the objects.

Create row objects​

{template high-level-style-object%%}

Insert data​

{template high-level-style-insert-data%%}

Streaming insert​

Streaming insert is useful when you want to insert a large amount of data such as importing historical data.

{template high-level-style-streaming-insert%%}

{template high-level-style-update-data%%}

More examples​

{template more-ingestion-examples%%}

{template ingester-lib-debug-logs%%}

Ingester library reference​

{template ingester-lib-reference%%}

Query data​

GreptimeDB uses SQL as the main query language and is compatible with MySQL and PostgreSQL. Therefore, we recommend using mature SQL drivers to query data.

{template recommended-query-library%%}

Installation​

{template query-library-installation%%}

Connect to database​

The following example shows how to connect to GreptimeDB:

{template query-library-connect%%}

Raw SQL​

We recommend you using raw SQL to experience the full features of GreptimeDB. The following example shows how to use raw SQL to query data.

{template query-library-raw-sql%%}

Query library reference​

For more information about how to use the query library, please see the documentation of the corresponding library:

{template query-lib-doc-link%%}