sqloader 0.2.0

A simple and extensible SQL migration and loader utility for Python.

sqloader

A lightweight Python utility for managing SQL migrations and loading SQL from JSON or .sql files. Supports MySQL, PostgreSQL, and SQLite with clean integration for any Python backend (e.g., FastAPI).

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Installation

pip install sqloader

Features

• Easy database migration management
• Load SQL queries from .json or .sql files
• Supports MySQL, PostgreSQL, and SQLite
• Integrated execution: sqloader.execute(), sqloader.fetch_one(), sqloader.fetch_all()
• Thread-safe connection pooling (Semaphore + psycopg2 SimpleConnectionPool)
• Transaction context manager with automatic commit / rollback
• Async support: asyncpg, aiomysql, aiosqlite
• Async integrated execution: await sqloader.async_execute(), await sqloader.async_fetchone(), await sqloader.async_fetchall()

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Quickstart

MySQL

from sqloader.init import database_init

config = {
    "type": "mysql",
    "placeholder": ["?", "%s"],
    "mysql": {
        "host": "localhost",
        "port": 3306,
        "user": "root",
        "password": "pass",
        "database": "mydb"
    },
    "service": {
        "sqloder": "res/sql/sqloader/mysql"
    },
    "migration": {
        "auto_migration": True,
        "migration_path": "res/sql/migration/mysql"
    },
}

db, sq, migrator = database_init(config)

# Classic usage
query = sq.load_sql("user", "get_user_by_id")
result = db.fetch_one(query, [123])

# Integrated usage (SQLoader runs the query directly)
result = sq.fetch_one("user", "get_user_by_id", [123])
rows   = sq.fetch_all("user", "get_all")
sq.execute("user", "update_name", ["Alice", 123])

PostgreSQL

config = {
    "type": "postgresql",
    "postgresql": {
        "host": "localhost",
        "port": 5432,
        "user": "postgres",
        "password": "pass",
        "database": "mydb",
        "max_parallel_queries": 10   # optional, default 5
    },
    "service": {
        "sqloder": "res/sql/sqloader/postgresql"
    },
    "migration": {
        "auto_migration": True,
        "migration_path": "res/sql/migration/postgresql"
    },
}

db, sq, migrator = database_init(config)
result = sq.fetch_one("user", "get_user_by_id", [123])

SQLite

config = {
    "type": "sqlite3",
    "sqlite3": {
        "db_name": "local.db"
    },
    "service": {
        "sqloder": "res/sql/sqloader/sqlite"
    },
}

db, sq, migrator = database_init(config)

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Async Usage

Async PostgreSQL (FastAPI example)

from sqloader.init import async_database_init

config = {
    "type": "postgresql",
    "postgresql": {
        "host": "localhost",
        "port": 5432,
        "user": "postgres",
        "password": "pass",
        "database": "mydb",
        "max_size": 10
    },
    "service": {
        "sqloder": "res/sql/sqloader/postgresql"
    },
}

db, sq = await async_database_init(config)

# Integrated async usage
result = await sq.async_fetchone("user", "get_user_by_id", [123])
rows   = await sq.async_fetchall("user", "get_all")
await sq.async_execute("user", "update_name", ["Alice", 123])

# Direct wrapper usage
result = await db.fetchone("SELECT * FROM users WHERE id = $1", [123])

Async MySQL

config = {
    "type": "mysql",
    "mysql": {
        "host": "localhost",
        "port": 3306,
        "user": "root",
        "password": "pass",
        "database": "mydb"
    },
    "service": {
        "sqloder": "res/sql/sqloader/mysql"
    },
}

db, sq = await async_database_init(config)
result = await sq.async_fetchone("user", "get_user_by_id", [123])

Async Transaction

async with db.begin_transaction() as txn:
    await txn.execute("INSERT INTO users (name) VALUES (%s)", ["Alice"])
    await txn.execute("UPDATE stats SET count = count + 1")

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SQL Loading Behavior

If a value in the .json file ends with .sql, the referenced file is loaded from the same directory. Otherwise the value is used directly as a SQL string.

user.json

{
  "get_user_by_id": "SELECT * FROM users WHERE id = %s",
  "get_all": "user_all.sql",
  "admin": {
    "bulk_delete": "DELETE FROM users WHERE id = %s"
  }
}

# Simple key
sq.fetch_one("user", "get_user_by_id", [123])

# Nested key (dot notation)
sq.execute("user", "admin.bulk_delete", [999])

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Transaction

with db.begin_transaction() as txn:
    txn.execute("INSERT INTO users (name) VALUES (%s)", ["Alice"])
    txn.execute("UPDATE stats SET count = count + 1")
    # Commits automatically on success, rolls back on exception

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Migration

Migration files are applied in filename-sorted order. Already applied files are skipped.

res/sql/migration/
    001_create_users.sql
    002_add_index.sql

Set auto_migration: True to apply pending migrations automatically during database_init().

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SQLoader Standalone Usage

from sqloader import SQLoader
from sqloader.mysql import MySqlWrapper

db = MySqlWrapper(host="localhost", user="root", password="pass", db="mydb")
sq = SQLoader("res/sql", db_type=2, db=db)  # db_type: MYSQL=2, POSTGRESQL=3, SQLITE=1

# Or inject later
sq = SQLoader("res/sql", db_type=2)
sq.set_db(db)

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Dependencies

Package	Purpose
pymysql >= 1.1.1	MySQL (sync)
psycopg2-binary >= 2.9.0	PostgreSQL (sync)
sqlite3	SQLite sync (Python standard library)
aiomysql >= 0.2.0	MySQL (async)
asyncpg >= 0.29.0	PostgreSQL (async)
aiosqlite >= 0.20.0	SQLite (async)