apgdiff

apgdiff is a free, Java-based command-line tool that compares two PostgreSQL schema dump files and generates SQL to update the older schema. It suits developers and database administrators comfortable working in a terminal who need a focused schema-diff step in a batch or web-application workflow. Its narrow scope and ignored SQL make careful review of its output essential.

Overview

Give apgdiff an original dump and a newer dump; it can print the resulting DDL or redirect it to a file. That makes it useful for producing migration scripts from a pair of snapshots without requiring a graphical interface. It compares dump files rather than offering a broader database-management environment, and its database scope is PostgreSQL alone.

The tool is MIT licensed and free. The download page identifies version 2.4 as the latest stable release; project news dates that release to 2012-09-21. It is a lean option for a bounded task, but teams seeking a current, actively evolving workflow should weigh that project history before adopting it.

Key features

apgdiff supports selected schema statements, including ALTER TABLE, ALTER SEQUENCE, CREATE TABLE, CREATE VIEW, CREATE FUNCTION, CREATE INDEX, CREATE TRIGGER, and comments. For teams whose dumps rely on those constructs, it can turn structural differences into upgrade DDL that can be saved as a migration script.

Its coverage is not a complete SQL parser: other statements are ignored, and CREATE TABLE column constraints are limited to NULL and NOT NULL. The --output-ignored-statements option can expose ignored DDL, which helps identify gaps, but does not make those statements part of the generated update. Review the output and consider testing it against another database before using it in production.

Because it runs in a terminal, apgdiff can fit scripts and batch jobs, but that same interface is a poor match for users who expect a graphical comparison tool. It is a Java program requiring Java 1.6 or newer. The supported-systems page names Linux, Windows, Mac OS X, Solaris, and BSD, and says other systems with Java may work.

Pricing

There is one plan: Free. It includes a free PostgreSQL schema-diff tool under the MIT License, with migration-script generation. There is no paid tier or free trial to weigh; the trade-off is the tool's restricted SQL coverage rather than a feature gate.

Platforms

apgdiff is listed for Linux, macOS, and Windows. Its Java runtime and the broader supported-systems guidance extend the stated reach to Solaris, BSD, and potentially other Java-capable systems.

Who it's for

Choose apgdiff if you work with PostgreSQL dumps, prefer command-line tools, and want to generate update DDL without paying for a schema-diff utility. It is less suitable for users who need broad SQL coverage, a graphical workflow, or a tool whose project history indicates more recent releases.

Pros and cons

• Pros: Free and MIT licensed, with no trial or subscription decision; generates DDL from two PostgreSQL schema dumps and can save it as a migration script.
• Pros: Command-line operation makes it suitable for batch or web-application workflows, and the ignored-statement option helps flag some coverage gaps.
• Cons: It ignores unsupported SQL, while column constraints in CREATE TABLE are limited to NULL and NOT NULL, so generated updates need scrutiny.
• Cons: The terminal interface will inconvenience users who are not accustomed to command-line applications, and version 2.4 dates to 2012.

Alternatives

For a broader comparison of tools in this category, see Database Schema Comparison Tools.

• dbForge Studio for PostgreSQL is worth considering if you want a free limited-feature Express plan, a free trial, or a paid Standard plan at $89.95 a year.
• Skeema suits readers comparing free Community coverage for tables, stored procedures, functions, and 18 linter checks with a Plus plan at $124/month or
• sqldef is another free, open-source CLI option for Linux, macOS, Windows, and self-hosted use.
• pgquarrel is a free BSD-3-Clause alternative for Linux, Windows, and self-hosted use.
• dbdiff is another free option with Linux, macOS, Windows, and self-hosted platform support.
• DBDiff is a free alternative described by Akal Software as an open-source project.
• DBC is another free option for Linux, macOS, and Windows.
• Redgate SQL Provision is a paid alternative with a free trial and capacity tiers based on production data volume.

Verdict

apgdiff is a sensible choice for command-line users who need a free, focused way to derive PostgreSQL migration DDL from schema dumps. Its simplicity and MIT license are compelling for that specific job; look elsewhere if you need broader SQL coverage, a graphical workflow, or a more recent release history.