chdb-datastore

# chdb DataStore — It's Just Faster Pandas ## The Key Insight ```python # Change this: import pandas as pd # To this: import chdb.datastore as pd # Everything else stays the same. ``` DataStore is a **lazy, ClickHouse-backed pandas replacement**. Your existing pandas code works unchanged — but operations compile to optimized SQL and execute only when results are needed (e.g., `print()`, `len()`, iteration). ```bash pip install chdb ``` ## Decision Tree: Pick the Right Approach ``` 1. "I have a file/database and want to analyze it with pandas" → DataStore.from_file() / from_mysql() / from_s3() etc. → See references/connectors.md 2. "I need to join data from different sources" → Create DataStores from each source, use .join() → See examples/examples.md #3-5 3. "My pandas code is too slow" → import chdb.datastore as pd — change one line, keep the rest 4. "I need raw SQL queries" → Use the chdb-sql skill instead ``` ## Connect to Any Data Source — One Pattern ```python from datastore import DataStore # Local file (auto-detects .parquet, .csv, .json, .arrow, .orc, .avro, .tsv, .xml) ds = DataStore.from_file("sales.parquet") # Database ds = DataStore.from_mysql(host="db:3306", database="shop", table="orders", user="root", password="pass") # Cloud storage ds = DataStore.from_s3("s3://bucket/data.parquet", nosign=True) # URI shorthand — auto-detects source type ds = DataStore.uri("mysql://root:pass@db:3306/shop/orders") ``` All 16+ sources and URI schemes → [connectors.md](references/connectors.md) ## After Connecting — Full Pandas API ```python result = ds[ds["age"] > 25] # filter result = ds[["name", "city"]] # select columns result = ds.sort_values("revenue", ascending=False) # sort result = ds.groupby("dept")["salary"].mean() # groupby result = ds.assign(margin=lambda x: x["profit"] / x["revenue"]) # computed column ds["name"].str.upper() # string accessor ds["date"].dt.year # datetime accessor result = ds1.join(ds2, on="id") # join result = ds.head(10) # preview print(ds.to_sql()) # see generated SQL ``` 209 DataFrame methods supported. Full API → [api-reference.md](references/api-reference.md) ## Cross-Source Join — The Killer Feature ```python from datastore import DataStore customers = DataStore.from_mysql(host="db:3306", database="crm", table="customers", user="root", password="pass") orders = DataStore.from_file("orders.parquet") result = (orders .join(customers, left_on="customer_id", right_on="id") .groupby("country") .agg({"amount": "sum", "rating": "mean"}) .sort_values("sum", ascending=False)) print(result) ``` More join examples → [examples.md](examples/examples.md) ## Writing Data ```python source = DataStore.from_mysql(host="db:3306", database="shop", table="orders", user="root", password="pass") target = DataStore("file", path="summary.parquet", format="Parquet") target.insert_into("category", "total", "count").select_from( source.groupby("category").select("category", "sum(amount) AS total", "count() AS count") ).execute() ``` ## Troubleshooting | Problem | Fix | | ---------------------------------------- | ------------------------------------------------------------------------------- | | `ImportError: No module named 'chdb'` | `pip install chdb` | | `ImportError: cannot import 'DataStore'` | Use `from datastore import DataStore` or `from chdb.datastore import DataStore` | | Database connection timeout | Include port in host: `host="db:3306"` not `host="db"` | | Join returns empty result | Check key types match (both int or both string); use `.to_sql()` to inspect | | Unexpected results | Call `ds.to_sql()` to see the generated SQL and debug | | Environment check | Run `python scripts/verify_install.py` (from skill directory) | ## References - [API Reference](references/api-reference.md) — Full DataStore method signatures - [Connectors](references/connectors.md) — All 16+ data source connection methods - [Examples](examples/examples.md) — 10+ runnable examples with expected output - [Verify Install](scripts/verify_install.py) — Environment verification script - [Official Docs](https://clickhouse.com/docs/chdb) > Note: This skill teaches how to _use_ chdb DataStore. > For raw SQL queries, use the `chdb-sql` skill. > For contributing to chdb source code, see CLAUDE.md in the project root.