# Sprint 56 Plan: Data and Query Family (SQL Dialects + Dataflow)

## Context

SQL/TSQL/PostgreSQL/MySQL semantics and transaction behavior are central in real
legacy systems. Sprint 56 adds explicit query and transaction intent modeling.

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## Goals

1. Normalize SQL dialect semantics into IR query model
2. Preserve transaction and isolation intent across projections
3. Support query->application-layer and application->query projections
4. Add risk gates for semantic shifts in joins/null/aggregation behavior

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## Steps

### Step 789: SQL canonical query IR layer (12 tests)
### Step 790: PostgreSQL lowering/raising adapters (10 tests)
### Step 791: T-SQL lowering/raising adapters (10 tests)
### Step 792: MySQL lowering/raising adapters (10 tests)
### Step 793: Transaction/isolation semantics packet model (10 tests)
### Step 794: Query behavior equivalence runner (set-based diff checks) (10 tests)
### Step 795: Null/join/aggregation divergence classifier (8 tests)
### Step 796: `whetstone_transpile_query_family` MCP tool (8 tests)
### Step 797: Data family acceptance report (8 tests)
### Step 798: Sprint 56 integration summary + regression (8 tests)

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## Gate Requirement

- Query projections must include semantic diff evidence for representative datasets.