75 lines
2.3 KiB
Markdown
75 lines
2.3 KiB
Markdown
# Plan: ID Generators & Sequence System
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## Goal
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Add auto-generated ID support to BaraDB so users don't need to manually supply IDs on INSERT.
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## Phase 1: ID Generators
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### 1.1 AUTO_INCREMENT on INTEGER columns
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- Add `AUTO_INCREMENT` keyword to lexer
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- Parse in CREATE TABLE: `id INTEGER PRIMARY KEY AUTO_INCREMENT`
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- Store auto-increment state per table in ExecutionContext (counter)
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- On INSERT without explicit ID → auto-populate with next value
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- Thread-safe counter (atomic increment)
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### 1.2 SERIAL / BIGSERIAL as syntactic sugar
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- `SERIAL` = `INTEGER AUTO_INCREMENT`
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- `BIGSERIAL` = `BIGINT AUTO_INCREMENT`
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- Already partially parsed — wire to auto-increment logic
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### 1.3 UUID generation
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- Add `gen_random_uuid()` or `uuid()` as built-in function
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- Can be used in INSERT: `INSERT INTO t (id) VALUES (uuid())`
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- Also usable as DEFAULT: `id UUID DEFAULT uuid()`
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- Use Nim's std/oids or crypto random
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### 1.4 RETURNING clause
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- After INSERT, return generated values
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- `INSERT INTO t (name) VALUES ('x') RETURNING id`
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- Already partially parsed — wire to execution
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### 1.5 CREATE SEQUENCE / nextval / currval
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- `CREATE SEQUENCE seq_name START 1 INCREMENT 1`
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- `nextval('seq_name')` → returns next value
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- `currval('seq_name')` → returns current value
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- Store sequences in ExecutionContext
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### 1.6 Snowflake ID (distributed)
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- 64-bit ID = timestamp(41) + node_id(10) + sequence(12)
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- `snowflake_id(node_id)` function
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- For future distributed use
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## Phase 2: JOIN Optimizations ✅
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### 2.1 Hash Join ✅
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- For equi-join ON a.col = b.col
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- Build hash table on smaller side, probe with larger
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- O(N+M) instead of O(N*M)
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### 2.2 Index Nested Loop Join ✅
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- If index exists on join column → probe index per left row
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- O(N * log M) instead of O(N*M)
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### 2.3 Merge Join
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- For sorted inputs
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- Two-pointer sweep O(N+M)
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- **Status:** Not yet implemented — can be added if needed
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## Phase 3: Foreign Key Enforcement ✅
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### 3.1 CASCADE DELETE ✅
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### 3.2 SET NULL on delete ✅
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### 3.3 RESTRICT on delete ✅
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### 3.4 ON UPDATE CASCADE ✅
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### 3.5 ON UPDATE SET NULL ✅
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### 3.6 ON UPDATE RESTRICT ✅
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### 3.7 FK check on UPDATE (not just INSERT) ✅
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## Implementation Order
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1. AUTO_INCREMENT (lexer + parser + executor)
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2. SERIAL/BIGSERIAL sugar
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3. UUID function
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4. RETURNING clause
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5. Sequences (CREATE SEQUENCE / nextval / currval)
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6. Snowflake ID function
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