Baradb/PLAN_ID_GENERATORS.md

Plan: ID Generators & Sequence System

Goal

Add auto-generated ID support to BaraDB so users don't need to manually supply IDs on INSERT.

Phase 1: ID Generators

1.1 AUTO_INCREMENT on INTEGER columns

• Add AUTO_INCREMENT keyword to lexer
• Parse in CREATE TABLE: id INTEGER PRIMARY KEY AUTO_INCREMENT
• Store auto-increment state per table in ExecutionContext (counter)
• On INSERT without explicit ID → auto-populate with next value
• Thread-safe counter (atomic increment)

1.2 SERIAL / BIGSERIAL as syntactic sugar

• SERIAL = INTEGER AUTO_INCREMENT
• BIGSERIAL = BIGINT AUTO_INCREMENT
• Already partially parsed — wire to auto-increment logic

1.3 UUID generation

• Add gen_random_uuid() or uuid() as built-in function
• Can be used in INSERT: INSERT INTO t (id) VALUES (uuid())
• Also usable as DEFAULT: id UUID DEFAULT uuid()
• Use Nim's std/oids or crypto random

1.4 RETURNING clause

• After INSERT, return generated values
• INSERT INTO t (name) VALUES ('x') RETURNING id
• Already partially parsed — wire to execution

1.5 CREATE SEQUENCE / nextval / currval

• CREATE SEQUENCE seq_name START 1 INCREMENT 1
• nextval('seq_name') → returns next value
• currval('seq_name') → returns current value
• Store sequences in ExecutionContext

1.6 Snowflake ID (distributed)

• 64-bit ID = timestamp(41) + node_id(10) + sequence(12)
• snowflake_id(node_id) function
• For future distributed use

Phase 2: JOIN Optimizations (future)

2.1 Hash Join

• For equi-join ON a.col = b.col
• Build hash table on smaller side, probe with larger
• O(N+M) instead of O(N*M)

2.2 Index Nested Loop Join

• If index exists on join column → probe index per left row
• O(N * log M) instead of O(N*M)

2.3 Merge Join

• For sorted inputs
• Two-pointer sweep O(N+M)

Phase 3: Foreign Key Enforcement (future)

3.1 CASCADE DELETE

3.2 SET NULL on delete

3.3 RESTRICT on delete

3.4 ON UPDATE CASCADE

3.5 FK check on UPDATE (not just INSERT)

Implementation Order

1. AUTO_INCREMENT (lexer + parser + executor)
2. SERIAL/BIGSERIAL sugar
3. UUID function
4. RETURNING clause
5. Sequences (CREATE SEQUENCE / nextval / currval)
6. Snowflake ID function