Ryan Malloy
6819dd4cb0
Before:
cur.execute("SELECT CURRENT YEAR TO SECOND ...")
cur.fetchone() # → (b'\xc7\x14\x1a\x05\x04...',) raw BCD bytes
After:
cur.execute("SELECT CURRENT YEAR TO SECOND ...")
cur.fetchone() # → (datetime.datetime(2026, 5, 4, 12, 34, 56),)
Decoder picks the right Python type by qualifier:
YEAR/MONTH/DAY-only → datetime.date
HOUR/MIN/SEC-only → datetime.time
spans across both → datetime.datetime
Wire format (per IfxToJavaDateTime + Decimal.init treating as packed BCD):
byte[0] = sign + biased exponent (in base-100 digit pairs)
byte[1..] = BCD digit pairs: YYYY (2 bytes) + MM + DD + HH + MI + SS + FFFFF
Qualifier extraction from column descriptor:
encoded_length = (digit_count << 8) | (start_TU << 4) | end_TU
TU codes: YEAR=0, MONTH=2, DAY=4, HOUR=6, MIN=8, SEC=10,
FRAC1=11..FRAC5=15
Verified against four DATETIME columns of different qualifiers in
one tuple — see test_datetime_multiple_columns_in_one_row:
YEAR TO SECOND → datetime.datetime(2026, 5, 4, 12, 34, 56)
YEAR TO DAY → datetime.date(2026, 5, 4)
HOUR TO SECOND → datetime.time(12, 34, 56)
YEAR TO FRACTION(3) → datetime.datetime(...)
Module changes:
src/informix_db/converters.py:
+ _decode_datetime(raw, encoded_length) — qualifier-driven BCD walk
+ TU constants (_TU_YEAR, _TU_MONTH, ..., _TU_SECOND)
src/informix_db/_resultset.py:
+ DATETIME row-decoder branch — computes width from digit_count
in encoded_length high byte, calls _decode_datetime with the
packed qualifier so it can pick the right Python type
Tests: 40 unit + 70 integration (7 new DATETIME tests) = 110 total,
all green, ruff clean. Tests cover:
- YEAR TO SECOND → datetime.datetime
- YEAR TO DAY → datetime.date
- HOUR TO SECOND → datetime.time
- CURRENT YEAR TO FRACTION(3) → datetime.datetime
- Mixed qualifiers in one row
- DATETIME stored in a real table column (round-trip via SELECT)
- NULL DATETIME → Python None
DATETIME parameter binding (encoder) is Phase 6.x — same status as
DECIMAL encoder.
informix-db
Pure-Python driver for IBM Informix IDS, speaking the SQLI wire protocol over raw sockets. No IBM Client SDK. No JVM. No native libraries.
Status
🟢 Phase 1 complete. connect() / close() work end-to-end against a real Informix server. Cursor / execute / fetch land in Phase 2.
To our knowledge this is the first pure-socket Informix driver in any language — every other Informix driver (IfxPy, the legacy informixdb, ODBC bridges, Perl DBD::Informix) wraps either IBM's CSDK or the JDBC JAR.
Quick start
import informix_db
with informix_db.connect(
host="127.0.0.1", port=9088,
user="informix", password="in4mix",
database="sysmaster", server="informix",
) as conn:
# cursor() / execute() / fetchone() arrive in Phase 2
pass
Test against the official Informix dev container
docker compose -f tests/docker-compose.yml up -d # IBM Developer Edition, pinned by digest
uv sync --extra dev
uv run pytest # 34 unit tests (no Docker needed)
uv run pytest -m integration # 6 integration tests (needs the container)
Phase 0 artifacts (still useful — they ARE the public reference)
docs/PROTOCOL_NOTES.md— byte-level wire-format reference, derived from packet captures + JDBC decompilation, validated against a real serverdocs/JDBC_NOTES.md— index into the decompiled IBM JDBC driver's wire-protocol classesdocs/DECISION_LOG.md— running rationale for protocol / auth / type decisionsdocs/CAPTURES/— socat hex-dump captures of three reference scenarios (connect, SELECT, full DML cycle)tests/reference/RefClient.java— re-runnable JDBC ground-truth client for capturing fresh traces
License
MIT.