What problem does it solve? QuantDB stores market data across six dataset directories with mixed layouts (Hive-partitioned vs single-file parquet) and two conflicting stock code formats, so engineers frequently write queries that silently return empty results or scan the wrong partitions. This Skill provides the authoritative reference for where data lives, how it is organized, and how to read it correctly. ## Core Features & Use Cases - Directory & Partition Map: Documents the six top-level datasets (1_kline_data through 6_ml_datasets), the integer dt=YYYYMMDD Hive partition convention, and single-file vs partitioned storage rules. - Code Format Conversion Rules: Explains the suffix-style format (600519.SH) used in QuantDB parquet versus the prefix-style format (SH600519) used in PostgreSQL internal tables, and the conversion utilities that prevent silent empty-query failures. - Read Entry Points: Lists the quantdb_hub.py single read entry, all qdb_* DuckDB views, server path mappings (/opt/quantmind/data/quantdb to container /data/quantdb), and a pre-coding self-check checklist. - Use Case: When a DuckDB query against daily kline data returns zero rows, use this Skill to verify the dt filter is an integer, the symbol is suffix-style, and the partition directory actually exists on the server. ## Quick Start Ask the AI to explain where QuantDB stores forward-adjusted daily kline data and how to query it for symbol 600519.SH between two dates.