Enhance README with tool features and quick start

Expanded README with detailed tool description and highlights.

Author: arturormk

README.md

@@ -1,2 +1,20 @@
 # ods2sql-python
 One-file, pure-stdlib Python tool that converts instrumented LibreOffice .ods sheets into SQL for SQLite/Postgres/MySQL.
+
+ods2sql-python is a single-file, dependency-free CLI that reads native LibreOffice Calc .ods files (via zipfile + xml.etree) and emits SQL you can pipe directly into your database. Instrument your sheet with a tiny first-column markup (sqltable, header, sqltype, comment) and get reproducible CREATE TABLE and INSERT statements—perfect for quick ETL, data audits, and sharing spreadsheet data as a real database.
+
+## Highlights
+
+- Pure standard library (no external deps)
+- Multiple sheets & tables per file
+- Column selection via header; types via sqltype (defaults to TEXT)
+- Dialects: SQLite (default), Postgres, MySQL (quoting + booleans)
+- Fast batched INSERTs; --schema-only, --data-only, --list, --table
+- Emits SQL on stdout; diagnostics on stderr (pipe-safe)
+
+## Quick start
+
+```bash
+./ods2sql.py data.ods | sqlite3 data.sqlite
+./ods2sql.py data.ods --dialect postgres --batch 1000 > load.sql
+```