feat(jdbc): JdbcExporter, matching the CSV and Parquet exporters

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Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
25/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Active
Tech stack
java, sql
Domain
database

Research direction

Start by comparing the existing JdbcImporter and JdbcImportOptions with the CSV and Parquet exporter APIs to locate the JDBC module’s conventions. Then review the import type mapping and exporter progress listener patterns before defining the export API and binder behavior. Done means exporting rows into a caller-provided table in batches with validity-aware nulls, transaction rollback on failure, restored auto-commit, and opt-in DDL support.

Written by the indexing model from the issue text.

Description

enhancement good first issue

vortex-jdbc only has JdbcImporter/JdbcImportOptions; csv and parquet each have an importer and an exporter. Add JdbcExporter + JdbcExportOptions for symmetry: read a Vortex file and move its rows into a table in a JDBC database over a caller-supplied Connection.

API sketch

JdbcExportOptions opts = JdbcExportOptions.defaults()
        .withBatchSize(5_000)
        .withBinder(JdbcBinder.standard()
                .with(DType.Extension.class, (ps, i, value) -> ps.setObject(i, value)));

JdbcExporter.export(vortexPath, connection, "ohlc", opts);
  • Options are a final class with a private constructor, defaults() and withXxx copies, as everywhere else. The target table is a required argument of export, not an option (confirm that CsvExporter/ParquetExporter take their target the same way).
  • Binder (callback): a small functional interface that sets one value on a PreparedStatement. JdbcBinder.standard() covers primitives, strings, decimals, booleans and dates. A user overrides only the types their database needs special handling for (Postgres arrays, setObject for timestamps).
  • DDL helper, not automatic: a DType to SQL type function plus createTableSql(name, dtype) returns a CREATE TABLE string. The exporter never creates or alters a table on its own; creation is opt-in.

Behavior

  • Appends to an existing table with INSERT INTO t (cols...) VALUES (?, ...) through a PreparedStatement. Nulls follow the validity mask.
  • One transaction for the whole export: remember the connection's auto-commit setting, setAutoCommit(false), addBatch() per row, executeBatch() every batchSize rows, commit() at the end, rollback() and rethrow on failure, and restore auto-commit in a finally. The connection belongs to the caller. A failed export leaves nothing behind.
  • ProgressListener, as in the other exporters.

Open design questions

  • Reverse type mapping DType to SQL type (the inverse of SqlTypeToDType); it varies by database.
  • Create-if-missing vs truncate vs fail-if-exists: all opt-in, append is the default.
  • A withCommitEvery(n) option for very large exports, if a long-lived transaction proves a problem. Not in the first cut.

Not needed for the jdbc:vortex: driver work (#566). No demand yet, so this waits until someone needs it.

Dominant language
Java
Stars
3
Forks
2
Avg merge
9h 19m
Merged PRs (30d)
154

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