Docs

Short notes on the schema problems Schemint flags and on what it generates. No fluff, with real SQL and Java.

• From CREATE TABLE to JPA Entity: the type mapping How PostgreSQL types map to Java in a JPA Entity: identity, BigDecimal, timestamps, wrappers, and why.
• PostgreSQL doesn't index your foreign keys Why FKs get no index automatically, what it costs in joins and deletes, and the query to find the missing ones.
• That VARCHAR status column is an enum in denial CHECK constraint, native ENUM or lookup table: how to pick, and how to map it with @Enumerated in JPA.
• Money in PostgreSQL and Java: NUMERIC and BigDecimal Why float breaks money math, how to size NUMERIC, and the three classic BigDecimal traps.
• created_at and updated_at: database DEFAULT or JPA annotation? Pick one source for audit timestamps, and when timestamptz beats timestamp.
• From JSON to Pydantic and TypeScript models Inferring a schema from real payloads: mixed types, optional vs nullable fields, and date formats.
• SQL schema diff: spotting breaking changes before deploy Which schema changes break running clients, which don't, and the expand/contract pattern for the rest.
• Tables without a primary key: what actually goes wrong Duplicates, replication, ORMs and unaddressable rows: why even staging tables deserve an id.

Generators

Paste a schema or a JSON and get the models. Each opens with a live example.

• PostgreSQL CREATE TABLE to TypeScript interface Generate a TypeScript interface from a PostgreSQL CREATE TABLE. Nullable columns become optional; BIGINT and NUMERIC are yours to map to number or string.
• PostgreSQL CREATE TABLE to Pydantic model Generate a Pydantic v2 model from a PostgreSQL CREATE TABLE: Optional for nullable columns, Decimal for money, datetime for timestamps.
• PostgreSQL CREATE TABLE to SQLAlchemy model Generate a SQLAlchemy 2.0 model from a PostgreSQL CREATE TABLE: typed Mapped columns, primary key, nullable and unique constraints.
• PostgreSQL CREATE TABLE to SQLModel Generate a SQLModel class from a PostgreSQL CREATE TABLE: table=True, primary key Field, Optional for nullable columns.
• PostgreSQL CREATE TABLE to JPA Entity (Spring Boot) Generate a JPA @Entity from a PostgreSQL CREATE TABLE: @Id, @GeneratedValue, @Column with nullable/unique/length, BigDecimal for NUMERIC.
• PostgreSQL CREATE TABLE to Flyway migration Turn a PostgreSQL CREATE TABLE into a versioned Flyway migration (V1__...sql) with normalized DDL and FK-aware table ordering.
• JSON to TypeScript interface Generate a TypeScript interface from a JSON payload. Types are inferred from real values; nullable and optional fields are handled.
• JSON to Pydantic model Generate a Pydantic v2 model from a JSON payload. Types are inferred from real values; optional and nullable fields are handled.