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PostgresColumn¶

Column definitions for Postgres targets.

Usage¶

from bollhav.postgres import PostgresColumn, PostgresType

PostgresColumn(
    name="amount",
    data_type=PostgresType.NUMERIC,
    nullable=False,
    order=0,
    precision=18,
    scale=4,
    sensitive=False,
    description="Order total in USD",
)

Write Modes¶

See Write modes for the general concepts. Below describes the Postgres-specific implementation of each mode.

APPEND¶

Uses COPY ... FROM STDIN inside a transaction. No deduplication or conflict handling.

Pre-load flags: `recreate_table` / `truncate_table`¶

Both live on Target. They run once in ensure_table before the chunked write loop starts:

recreate_table=True → DROP TABLE IF EXISTS then CREATE TABLE (schema reset).
truncate_table=True → CREATE TABLE IF NOT EXISTS then TRUNCATE TABLE (rows wiped, schema kept).

Both default to False; setting both raises. Combine with any write mode — typically APPEND for a full reload, or UPSERT_NO_DELETE when you also want dedup after the wipe.

RECREATE_PARTITION¶

Requires since and until (UTC-aware datetimes) and target.partitioned_by to be set. Deletes rows where the partition column is >= since AND < until, then uses COPY. All in one transaction. IDEMPOTENT.

UPSERT_NO_DELETE¶

Loads data into a temp table via COPY, then runs INSERT ... ON CONFLICT (...) DO UPDATE SET .... Requires target.unique_columns to be set. The temp table is dropped on commit.

Views¶

A view is materialization=Materialization.VIEW on the model, not a write mode. Runs CREATE OR REPLACE VIEW from the model's query (its SELECT body, required for a view). No dataframe needed.