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 ✅

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)
• Status: Not yet implemented — can be added if needed

Phase 3: Foreign Key Enforcement ✅

3.1 CASCADE DELETE ✅

3.2 SET NULL on delete ✅

3.3 RESTRICT on delete ✅

3.4 ON UPDATE CASCADE ✅

3.5 ON UPDATE SET NULL ✅

3.6 ON UPDATE RESTRICT ✅

3.7 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