db-migration-oracle-postgres

db-migration-oracle-postgres is a skill for Claude Code, Codex from sandeepmvl/rails-skills. It costs 122 tokens per session (1,621 once invoked), scanned A, original, MIT.

A migration guide for moving a Ruby on Rails application's database from Oracle to PostgreSQL. Oracle and PostgreSQL use different data types, query features, database procedures, and adapters.

In plain words
What is it for?
Use it to audit Oracle objects, convert types and queries, translate PL/SQL where needed, move data with ora2pg, change to the `pg` adapter, and plan a dual-write cutover.
Why use it?
It helps reveal database-specific code that automated conversion may miss, especially stored procedures, triggers, views, and hierarchical queries. It also outlines how to move data and switch the Rails database connection safely.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to audit Oracle objects, convert types and queries, translate PL/SQL where needed, move data with ora2pg, change to the pg adapter, and plan a dual-write cutover.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/sandeepmvl/rails-skills/23-db-migration-oracle-postgres
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add sandeepmvl/rails-skills --skill 23-db-migration-oracle-postgres
Clone the repo
git clone --depth 1 https://github.com/sandeepmvl/rails-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for db-migration-oracle-postgres

README.md
[![agentmods](https://agentmods.dev/badge/skills/sandeepmvl/rails-skills/23-db-migration-oracle-postgres/github.svg)](https://agentmods.dev/skills/sandeepmvl/rails-skills/23-db-migration-oracle-postgres)
Your own site
<a href="https://agentmods.dev/skills/sandeepmvl/rails-skills/23-db-migration-oracle-postgres"><img src="https://agentmods.dev/badge/skills/sandeepmvl/rails-skills/23-db-migration-oracle-postgres/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for db-migration-oracle-postgres

Your own site · 80×15
<a href="https://agentmods.dev/skills/sandeepmvl/rails-skills/23-db-migration-oracle-postgres"><img src="https://agentmods.dev/badge/skills/sandeepmvl/rails-skills/23-db-migration-oracle-postgres.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 122 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,621 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00122 $0.01621
Opus 5 $0.00061 $0.00811
Sonnet 5 $0.00024 $0.00324
Haiku 4.5 $0.00012 $0.00162

Measured 11d ago against content hash e99ebf988afa, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

db-migration-oracle-postgres scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 11d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/23-db-migration-oracle-postgres/SKILL.md · 165 lines

How it starts

The opening of the file, as written. The whole thing — 165 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Oracle → Postgres Migration

Oracle to Postgres is a license-cost play more than a feature-set play. Most things move cleanly via ora2pg. The big risks are PL/SQL business logic in the database (Postgres has PL/pgSQL; not a direct translation), hierarchical queries (CONNECT BYWITH RECURSIVE), and Oracle-specific feature dependencies.

The opinion

Use ora2pg for schema + data conversion. Audit every PL/SQL package, trigger, and view — these don't translate automatically. Dual-write cutover for non-trivial apps. Switch from activerecord-oracle_enhanced-adapter to pg. Expect 4-12 weeks for a non-trivial enterprise app.

Pre-migration audit

# What lives in Oracle that isn't ActiveRecord SQL?
sqlplus user/pass@db <<EOF
  SELECT object_type, COUNT(*) FROM user_objects GROUP BY object_type;
  SELECT name FROM user_source WHERE type = 'PACKAGE';
EOF
Oracle feature Postgres equivalent Translation
NUMBER (precision varies) BIGINT, INTEGER, DECIMAL(p,s) Per-column decision based on usage
VARCHAR2(n) VARCHAR(n) Direct
CLOB / BLOB TEXT / BYTEA Direct
DATE (with time) TIMESTAMPTZ Watch timezone semantics
SEQUENCEs Sequences (also true sequences in PG) Direct
ROWID ctid (ephemeral) or surrogate id Usually means "stop relying on ROWID"
ROWNUM LIMIT / ROW_NUMBER() OVER (...) Direct rewrite
CONNECT BY ... START WITH WITH RECURSIVE Manual rewrite
PL/SQL packages PL/pgSQL functions Manual port — biggest risk
Triggers Triggers Mostly direct; syntax differs
Materialized views Materialized views Direct
NVL(x, y) COALESCE(x, y) Direct
SYSDATE NOW() / CURRENT_TIMESTAMP Direct
DBMS_* packages None (rewrite to app code or PG extension) Per-package decision

Core patterns

Pattern 1: ora2pg for schema + data

# Install
brew install ora2pg

# Generate config
ora2pg --project_base /path/to/migration --init_project myapp

# Schema export
ora2pg -t TABLE -o schema.sql
ora2pg -t SEQUENCE -o sequences.sql
ora2pg -t INDEX -o indexes.sql
ora2pg -t FUNCTION -o functions.sql
ora2pg -t PACKAGE -o packages.sql  # AUDIT THIS BY HAND

# Data export
ora2pg -t COPY -o data.sql  # COPY format, faster than INSERT

Read the full file on GitHub · 165 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 11d ago First seen · 165 lines · 122 tokens per session scan A e99ebf988afa

Subscribe to this mod's changes

db-migration-oracle-postgres is a skill published in the GitHub repository sandeepmvl/rails-skills (21 stars, last pushed 3mo ago), licensed MIT. It adds 122 tokens to every session and 1,621 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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