Read table metadata

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Tools read metadata to discover tables and columns. This page shows supported information_schema queries for an existing listener.

Before you run it: SHOW forms are refused. Do not assume ORM schema synchronization or every discovery query is compatible.

Metadata means information about the table, not its customer rows. The queries below look for namespace shop and table orders; change those filters to the namespace and table you actually created. An empty catalog result can mean the filter names do not match.

Follow the exampleCopy Anchor Link

1. Connect with the documented permissions.
2. Run the catalog queries.
3. Compare results with your tool’s requirements.
4. Declare models explicitly when automatic discovery is unsupported.

Supported catalog queriesCopy Anchor Link

Five views, served by the same shared catalog the other wire protocols read: tables, columns, table_constraints, key_column_usage, referential_constraints.

-- List the tables in a schema.
SELECT table_name
  FROM information_schema.tables
 WHERE table_schema = 'shop';

-- Describe one table's columns.
SELECT column_name, data_type, is_nullable
  FROM information_schema.columns
 WHERE table_schema = 'shop' AND table_name = 'orders';

-- Constraints, and the columns they cover.
SELECT constraint_name, constraint_type FROM information_schema.table_constraints
 WHERE table_name = 'orders';
SELECT constraint_name, column_name FROM information_schema.key_column_usage
 WHERE table_name = 'orders';

Unsupported catalog queriesCopy Anchor Link

SHOW TABLES;                      -- refused
SHOW DATABASES;                   -- refused
SHOW COLUMNS FROM orders;         -- refused
SHOW CREATE TABLE orders;         -- refused
SHOW INDEX FROM orders;           -- refused
SHOW WARNINGS;                    -- refused
SHOW VARIABLES LIKE 'sql_mode';   -- refused

The refusal is deliberate, and it is the safer of the two options. The shared front door carries a compatibility shim for a different protocol that answers any SHOW x with a single fabricated row reading x = 'on'. Left alone, SHOW TABLES would return that row: a confident, wrong answer. Refusing at the dialect boundary turns it into an error you can see.

Configure the ORM explicitlyCopy Anchor Link

// Safe: you tell the ORM the shape, it never asks the database.
const Order = sequelize.define(
  "Order",
  {
    id: { type: DataTypes.STRING, primaryKey: true },
    customer: DataTypes.STRING,
    total_cents: DataTypes.INTEGER,
    status: DataTypes.STRING,
  },
  { tableName: "orders", timestamps: false, freezeTableName: true },
);

// Not safe on this listener - each of these introspects with SHOW:
//   await sequelize.sync();
//   await sequelize.getQueryInterface().describeTable("orders");
//   await sequelize.getQueryInterface().showIndex("orders");

// Also not available: associations. Model the join in your query instead of
// asking the ORM to follow a relation for you.
//   Order.belongsTo(Customer);   // will not load

Check compatibility before adoptionCopy Anchor Link

This listener suits explicitly declared ORM models and the documented single-table queries. Association loading is not supported. For other operations, check the SQL endpoint. Current PostgreSQL database logins remain read-only; they do not provide universal ORM parity.

MySQL is a registered trademark of Oracle Corporation and/or its affiliates. OriginChainDB is not affiliated with, endorsed by, or sponsored by Oracle Corporation. OriginChainDB implements a compatible wire protocol so that existing MySQL clients can connect to it; it does not distribute MySQL software.

Expected resultCopy Anchor Link

Supported views return table, column and constraint information.

ContinueCopy Anchor Link

Continue to run sql on an existing mysql listener.