MySQL with Desi¶

Desi connects to MySQL using a pure C wire protocol — no libmysqlclient dependency. Everything is bundled in libdesi.a.

Connecting¶

import db

# Connect to MySQL
let status = db.connect("mysql", "localhost", 3306, "mydb", "root", "password")
if db.is_connected() != 1:
    print(f"Error: {db.last_error()}")

The driver accepts "mysql", "my", or "mariadb".

Querying¶

# SELECT — returns number of rows
let rows = db.query("SELECT id, name, email FROM users WHERE age > 21")

# Access results
for i in range(rows):
    let name = db.get_field(i, "name")
    let email = db.get_field(i, "email")
    print(f"{name}: {email}")

# Or by column index
let first_name = db.get_value(0, 1)

Executing¶

# INSERT/UPDATE/DELETE — returns affected row count
let inserted = db.execute("INSERT INTO users (name, age) VALUES ('Alice', 30)")
let updated = db.execute("UPDATE users SET age = 31 WHERE name = 'Alice'")
let deleted = db.execute("DELETE FROM users WHERE id = 5")

Raw SQL — Full MySQL Power¶

# Subqueries
db.query("SELECT * FROM users WHERE id IN (SELECT user_id FROM orders)")

# JSON support (MySQL 5.7+)
db.query("SELECT JSON_EXTRACT(metadata, '$.theme') FROM settings")

# Multi-table UPDATE
db.execute("UPDATE orders o JOIN users u ON o.user_id = u.id SET o.status = 'active' WHERE u.active = 1")

# USE another database
db.execute("USE other_database")

# Variables
db.execute("SET @max_age = 50")
db.query("SELECT * FROM users WHERE age < @max_age")

ORM Field Types¶

ORM Field	MySQL Type	Notes
`auto_field`	`INT AUTO_INCREMENT PRIMARY KEY`
`int_field`	`INTEGER`
`bigint_field`	`BIGINT`
`char_field`	`VARCHAR(n)`
`text_field`	`TEXT`
`bool_field`	`TINYINT(1)`	0/1
`float_field`	`DOUBLE`
`decimal_field`	`DECIMAL(p,s)`	Exact numeric
`datetime_field`	`DATETIME`	No timezone conversion
`json_field`	`JSON`	MySQL 5.7+
`uuid_field`	`VARCHAR(36)`	Stored as string
`array_field`	`JSON`	Arrays stored as JSON
`inet_field`	`VARCHAR(45)`	IPv4/IPv6 as string
`foreign_key`	`INTEGER REFERENCES`	InnoDB FK
`custom_field`	(any type)	Pass-through

ORM Example¶

import db

# Define model
db.model("products")
db.auto_field("id")
db.uuid_field("sku", 0, 1)
db.char_field("name", 200, 0, 0)
db.decimal_field("price", 10, 2, 0)
db.bool_field("available", 1, 0)
db.datetime_field("created_at", 0, 1, 0)
db.json_field("attributes", 1)
db.custom_field("status", "ENUM('draft','published','archived')", 0)

# Connect and create
db.connect("mysql", "localhost", 3306, "shop", "root", "pass")
let sql = db.create_table_sql("products")
db.execute(sql)

Generated SQL:

CREATE TABLE IF NOT EXISTS products (
  id INT AUTO_INCREMENT PRIMARY KEY,
  sku VARCHAR(36) NOT NULL UNIQUE,
  name VARCHAR(200) NOT NULL,
  price DECIMAL(10,2) NOT NULL,
  available TINYINT(1) NOT NULL DEFAULT TRUE,
  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
  attributes JSON,
  status ENUM('draft','published','archived') NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4

Debugging¶

db.set_debug(1)           # logs all protocol messages to stderr
db.dump_results()         # prints formatted result table
print(db.connection_info())
print(db.driver())        # → "mysql"

Authentication¶

Supported MySQL auth methods: - mysql_native_password — SHA1-based (MySQL 5.x default) - caching_sha2_password — Fast auth (MySQL 8.x default) - Auth method switch — Server-initiated plugin change

MySQL-Specific Notes¶

ENGINE=InnoDB — Auto-set on all ORM tables for transaction support
utf8mb4 — Full Unicode by default (supports emoji)
TIMESTAMP vs DATETIME — ORM uses DATETIME (no UTC auto-conversion; use TIMESTAMP via custom_field if needed)

Cleanup¶

db.close()