✦TL;DR

Complete API reference for BaseSQLHandler - the concrete implementation of HandlerInterface for SQL-based data sources.

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BaseSQLHandler

Class

📁application_sdk.handlers.sql

Inheritance chain:

HandlerInterface

A concrete implementation of HandlerInterface specifically designed for interacting with SQL-based data sources. Uses SQLClient for database communication and provides SQL query-driven behavior with configurable SQL queries for common operations.

SQL Queries

test_authentication_sqlstr

Query to test connection/authentication. Used by test_auth() method.

Default: "SELECT 1;"

client_version_sqlstr

Query to fetch database client version. Used in check_client_version() within preflight_check().

metadata_sqlstr

Query to fetch database and schema names together. Used by prepare_metadata() called by fetch_metadata().

tables_check_sqlstr

Query to count tables based on filters. Used by tables_check() within preflight_check().

fetch_databases_sqlstr

Query to fetch only database names. Used when metadata_type is 'database'.

fetch_schemas_sqlstr

Query to fetch schema names for a given database. Used when metadata_type is 'schema'.

Methods5

▸

__init__

__init__(self, sql_client)

Initialize the handler with a required SQLClient instance

Parameters

sql_clientSQLClient

Required

SQL client instance for database communication

▸

load

async

async load(self, credentials)

Calls load() on the provided SQL client with the given credentials

Parameters

credentialsdict

Required

Database authentication credentials

▸

test_auth

async

async test_auth(self, **kwargs) -> bool

Executes test_authentication_sql query using SQLQueryInput to test database connectivity

Parameters

kwargsdict

Required

Keyword arguments (typically empty for basic auth test)

Returns

bool - True if authentication succeeds, False otherwise

▸

preflight_check

async

async preflight_check(self, payload, **kwargs) -> dict

Orchestrates several checks: check_schemas_and_databases() (validates include/exclude filters), tables_check() (counts tables using tables_check_sql), and check_client_version() (verifies against SQL_SERVER_MIN_VERSION)

Parameters

payloaddict

Required

Payload containing configuration and filters

kwargsdict

Optional

Additional keyword arguments

Returns

dict - Dictionary with check results and overall success status

▸

fetch_metadata

async

async fetch_metadata(self, **kwargs) -> Any

Based on metadata_type argument, calls prepare_metadata() (executes metadata_sql), fetch_databases() (executes fetch_databases_sql), or fetch_schemas() (executes fetch_schemas_sql)

Parameters

kwargsdict

Required

Keyword arguments including metadata_type and filters

Returns

Any - Metadata based on the requested type

Usage Examples

Basic SQL Handler Usage

Create a BaseSQLHandler with a specific SQL client for database operations

from application_sdk.handlers.sql import BaseSQLHandler
from .clients import PostgreSQLClient

# Initialize with specific SQL client
client = PostgreSQLClient()
handler = BaseSQLHandler(sql_client=client)

# Use with Application
from application_sdk.server.fastapi import APIServer
app = APIServer(handler=handler)