SQLite Driver#

The SQLite driver provides access to SQLite databases.

Status#

The SQLite driver is essentially a “reference” driver that was used during ADBC development. It generally supports most ADBC features but has not received attention to optimization.

Installation#

The SQLite driver is shipped as a standalone library.

C++

See Contributing to build and install the package from source.

Python

pip install adbc_driver_sqlite

Usage#

To connect to a database, supply the “uri” parameter when constructing the AdbcDatabase. This should be a filename or URI filename. If omitted, it will default to an in-memory database, but one that is shared across all connections.

C++

#include "adbc.h"

// Ignoring error handling
struct AdbcDatabase database;
AdbcDatabaseNew(&database, nullptr);
AdbcDatabaseSetOption(&database, "uri", "file:mydb.db", nullptr);
AdbcDatabaseInit(&database, nullptr);

Python

import adbc_driver_sqlite.dbapi

with adbc_driver_sqlite.dbapi.connect() as conn:
    pass

Supported Features#

Bulk Ingestion#

Bulk ingestion is supported. The mapping from Arrow types to SQLite types is the same as below.

Partitioned Result Sets#

Partitioned result sets are not supported.

Transactions#

Transactions are supported.

Type Inference/Type Support#

SQLite does not enforce that values in a column have the same type. The SQLite driver will attempt to infer the best Arrow type for a column as the result set is read. When reading the first batch of data, the driver will be in “type promotion” mode. The inferred type of each column begins as INT64, and will convert to DOUBLE, then STRING, if needed. After that, reading more batches will attempt to convert to the inferred types. An error will be raised if this is not possible (e.g. if a string value is read but the column was inferred to be of type INT64).

In the future, other behaviors may also be supported.

Bound parameters will be translated to SQLite’s integer, floating-point, or text types as appropriate. Supported Arrow types are: signed and unsigned integers, (large) strings, float, and double.

Driver-specific options:

adbc.sqlite.query.batch_rows: The size of batches to read. Hence, this also controls how many rows are read to infer the Arrow type.