Cómo usar
- Copia el comando y revisa el paquete antes de instalarlo en tu entorno de agente.
- Consulta las herramientas, credenciales y entornos necesarios en el documento original.
- Describe las entradas y el resultado deseado; contrasta la salida con las fuentes.
npx skills add https://github.com/thaildhe172591/pythia --skill pythia-tableAntes de empezar
- La instalación no incluye suscripción al modelo, cuota API ni permisos sobre tus archivos.
- Las estrellas e instalaciones reflejan actividad, no una prueba independiente de calidad o seguridad.
Contenido del repositorio de origen con títulos, ejemplos, código, tablas, enlaces e imágenes preservados.
Tables, Columns, Comments
Announce at start: "Using pythia-table — reading the table and its neighbours before designing DDL."
Phase: Learn → Ask → Do — the table as it is, the decisions that are the developer's, then one ordered script
A table outlives every program that reads it. Its columns are a contract with every report, interface and procedure in the schema, and structural DDL has almost no undo: DROP COLUMN is permanent, a renamed column breaks every caller at once. Five minutes of design is the cheapest step there is.
The Iron Law
NO TABLE OR COLUMN WITHOUT ITS COMMENT, ITS CONSTRAINTS AND ITS IMPACT KNOWNThe Workflow
- Learn the table and its neighbours.
pythia cols T·pythia comments T·pythia stats T— what exists,
what is documented, which foreign keys lack an index.
pythia impact Tbefore any ALTER — every program that recompiles.pythia similar T_<NAME>andpythia ddl TABLE <NEIGHBOUR>— how this
house already builds tables: PK style, audit columns, tablespace, naming. Read .pythia/conventions.md and pythia conventions.
- Ask what is the developer's (through
pythia-spec): what is kept or
deleted, nullability of existing rows and the backfill value, retention, who writes the table (an API package, a trigger, an interface), identity column vs sequence when the house has no rule. Never invent a business default for a NOT NULL column.
- Write one ordered script —
reference/ddl-standards.mdhas the
template and the datatype rules:
- name every constraint (
PK_,FK_,UK_,CK_unless the house says
otherwise); a primary key on every table; an index on every FK column;
- text as
VARCHAR2(n CHAR)— a Vietnamese character can take 3 bytes;
money as NUMBER(p,s), never FLOAT; DATE or TIMESTAMP by need;
COMMENT ON TABLEandCOMMENT ON COLUMNfor every new table and
column: meaning, unit, allowed values, source. Vietnamese is fine here — COMMENT ... IS takes a literal only (no unistr), and pythia sends UTF-8 exactly; pythia doctor --db warns if the character set cannot hold it.
- Lint it:
pythia lint script.sql comments.sql(one run, so the
comments file counts) — missing comments, unnamed constraints, unindexed FKs, ADD ... NOT NULL without a default, byte-semantics text, missing house columns. Errors are fixed, not argued.
- Land it with
pythia-deploy(pythia deploy script.sql): every
statement previewed, one approval, run in order, stopped at the first failure. A single statement can go through pythia apply as usual. structural is deny by default — relay the refusal; the developer decides (pythia policy set structural confirm, or an autopilot lease naming structural).
- Verify (
pythia-verify):pythia cols T,pythia comments T(0
missing), pythia invalid against the baseline.
Changing a live table — expand, then contract
| Change | Safe shape |
|---|---|
| New mandatory column | ADD (c ... DEFAULT <agreed> NOT NULL) — one step, metadata-only on 12c+. No agreed default → add nullable, backfill (data_dml), then MODIFY c NOT NULL. |
| Rename | Never in place on a shared schema: add the new column, copy, move the callers, drop the old one later — a separate, destructive approval. |
| Type change | Widening (VARCHAR2(50) → (100)) is in place; anything narrowing or converting: new column, copy, swap. |
| New FK on existing data | ENABLE NOVALIDATE first, clean the rows, then VALIDATE — and the index before the constraint. |
| Drop | Destructive: its own preview, its own approval, never inside an autopilot lease unless the card said so. Check the Recycle Bin is on and never add PURGE without being asked. |
Big tables (millions of rows): ALTER TABLE ... ADD with a default is metadata-only, but MODIFY, index builds and backfills are not — ask about a window, and ONLINE index builds need Enterprise Edition. Partitioning and compression are separately licensed options: name that before proposing them.
Is rollback real?
| Statement | Undo |
|---|---|
COMMENT ON | Yes — the previous comment is snapshotted; pythia journal restore <entry>. |
CREATE TABLE / INDEX / SEQUENCE | A DROP — structural, written by hand, approved like any write. |
ALTER TABLE ADD | ALTER TABLE ... DROP COLUMN — the data written since is lost. |
DROP, TRUNCATE, SET UNUSED | No. Flashback is a DBA's job, if retention allows it. |
Red Flags — STOP if you catch yourself thinking
| Thought | Reality |
|---|---|
| "Comments later, once it works" | Later never comes; the dictionary is the only documentation that survives. Same script. |
| "The FK index is an optimisation" | Without it, deleting a parent locks the whole child table. It is correctness under load. |
| "VARCHAR2(100) is plenty" | 100 bytes is ~33 Vietnamese characters in AL32UTF8. Say CHAR. |
| "I'll default the NOT NULL column to 0" | That is a business decision made silently. Ask. |
| "Rename is one statement" | And one broken caller per reference. Expand, then contract. |
| "The table is new, impact is zero" | Say so with pythia impact as evidence — then it is a fact, not a guess. |
When NOT to use this skill
- Changing code that reads the table →
pythia-write/pythia-package. - A slow query on an existing table →
pythia-tune(an index is still
designed here once tuning asks for it).
- Data fixes (
UPDATE/DELETE) →pythia-apply; they aredata_dml.
