# Search Criteria SQL Extraction Functions - Design

## Purpose

Create SQL Server functions to extract values from the `Search.Criteria` JSON column, eliminating the need for C# to deserialize criteria and pass Table-Valued Parameters to SQL Server. The query builder will generate SQL that extracts filter values directly from the database.

## Goals

1. Create 11 SQL functions to extract scalar and table values from SearchCriteria JSON
2. Remove Table Type dependencies (7 TVP types)
3. Simplify C# query generation to pass only SearchId
4. Add comprehensive Database.Tests for the new functions
5. Update documentation and specifications

## Architecture

### SQL Server Version
- **Target:** SQL Server 2022
- **JSON Functions:** `OPENJSON()`, `JSON_VALUE()`, `ISJSON()`, `TRY_CONVERT()`

### Design Decision: Inline TVFs + Stored Procedure Validation

**Codex Review Findings:**
1. **THROW cannot be used in UDFs** - SQL Server restriction applies to all function types
2. **Multi-statement TVFs have poor performance** - Table variables lack statistics, causing bad cardinality estimates
3. **Inline TVFs are optimal** - Can be inlined into query plans with proper optimization

**Chosen Pattern:**
- **Inline TVFs** for extraction (performance-critical, used in query builder)
- **Validation stored procedure** for error handling when needed
- **C# validates search exists** before calling query builder (defense in depth)

### Function Types

**Scalar Functions (3):**
| Function | Returns | JSON Path |
|----------|---------|-----------|
| `dbo.fn_GetSearchMinimumDt` | `DATETIME2(7)` | `$.MinimumDt` |
| `dbo.fn_GetSearchMaximumDt` | `DATETIME2(7)` | `$.MaximumDt` |
| `dbo.fn_GetSearchExtractMisData` | `BIT` | `$.ExtractMisData` |

**Simple Table Functions (5) - Inline TVFs:**
| Function | Returns | JSON Path |
|----------|---------|-----------|
| `dbo.fn_GetSearchWorkOrders` | `TABLE(WorkOrderNumber BIGINT)` | `$.WorkOrderNumbers` |
| `dbo.fn_GetSearchItemNumbers` | `TABLE(ItemNumber VARCHAR(128))` | `$.ItemNumbers` |
| `dbo.fn_GetSearchProfitCenters` | `TABLE(Code VARCHAR(12))` | `$.ProfitCenters` |
| `dbo.fn_GetSearchWorkCenters` | `TABLE(Code VARCHAR(12))` | `$.WorkCenters` |
| `dbo.fn_GetSearchOperatorIDs` | `TABLE(OperatorID VARCHAR(128))` | `$.OperatorIDs` |

**Complex Table Functions (2) - Inline TVFs with OPENJSON...WITH:**
| Function | Returns | JSON Path |
|----------|---------|-----------|
| `dbo.fn_GetSearchComponentLots` | `TABLE(LotNumber VARCHAR(30), ItemNumber VARCHAR(128))` | `$.ComponentLotNumbers[*]` |
| `dbo.fn_GetSearchPartOperations` | `TABLE(ItemNumber VARCHAR(128), OperationNumber VARCHAR(10), MisNumber VARCHAR(10), MisRevision VARCHAR(10))` | `$.PartOperations[*]` |

**Validation Stored Procedure (1):**
| Procedure | Purpose |
|-----------|---------|
| `dbo.usp_ValidateSearchCriteria` | Validates search exists and has valid JSON, throws errors |

### Error Handling Strategy

**Two-tier approach:**

1. **Inline TVFs (graceful):** Return empty results for all edge cases
   - Search not found → empty
   - Criteria NULL/empty → empty
   - Invalid JSON → empty (ISJSON guard)
   - Property missing → empty
   - Bad data types → filtered out (TRY_CONVERT)

2. **Validation Procedure (strict):** Throws errors for invalid conditions
   - Used when explicit validation needed
   - Called before query execution if strict mode required

| Error Code | Condition | Message Pattern |
|------------|-----------|-----------------|
| 50001 | SearchId not found | `Search ID {id} not found` |
| 50002 | Criteria is NULL or empty | `Search ID {id} has no criteria` |
| 50003 | Criteria is invalid JSON | `Search ID {id} has invalid JSON` |

### Inline TVF Pattern (Simple Arrays)

```sql
CREATE FUNCTION dbo.fn_GetSearchWorkOrders(@SearchId INT)
RETURNS TABLE
AS
RETURN
(
    SELECT TRY_CONVERT(BIGINT, j.[value]) AS WorkOrderNumber
    FROM dbo.Search s
    CROSS APPLY OPENJSON(s.Criteria, '$.WorkOrderNumbers') j
    WHERE s.ID = @SearchId
      AND s.Criteria IS NOT NULL
      AND ISJSON(s.Criteria) = 1
      AND TRY_CONVERT(BIGINT, j.[value]) IS NOT NULL
);
GO
```

### Inline TVF Pattern (Complex Objects with OPENJSON...WITH)

```sql
CREATE FUNCTION dbo.fn_GetSearchComponentLots(@SearchId INT)
RETURNS TABLE
AS
RETURN
(
    SELECT j.LotNumber, j.ItemNumber
    FROM dbo.Search s
    CROSS APPLY OPENJSON(s.Criteria, '$.ComponentLotNumbers')
        WITH (
            LotNumber VARCHAR(30) '$.LotNumber',
            ItemNumber VARCHAR(128) '$.ItemNumber'
        ) j
    WHERE s.ID = @SearchId
      AND s.Criteria IS NOT NULL
      AND ISJSON(s.Criteria) = 1
);
GO
```

### Scalar Function Pattern

```sql
CREATE FUNCTION dbo.fn_GetSearchMinimumDt(@SearchId INT)
RETURNS DATETIME2(7)
AS
BEGIN
    DECLARE @Result DATETIME2(7);

    SELECT @Result = TRY_CONVERT(DATETIME2(7), JSON_VALUE(s.Criteria, '$.MinimumDt'))
    FROM dbo.Search s
    WHERE s.ID = @SearchId
      AND s.Criteria IS NOT NULL
      AND ISJSON(s.Criteria) = 1;

    RETURN @Result;
END
GO
```

### Validation Stored Procedure

```sql
CREATE PROCEDURE dbo.usp_ValidateSearchCriteria(@SearchId INT)
AS
BEGIN
    SET NOCOUNT ON;
    DECLARE @Criteria VARCHAR(MAX);
    DECLARE @ErrorMsg NVARCHAR(400);

    SELECT @Criteria = Criteria
    FROM dbo.Search
    WHERE ID = @SearchId;

    IF @@ROWCOUNT = 0
    BEGIN
        SET @ErrorMsg = CONCAT('Search ID ', @SearchId, ' not found');
        THROW 50001, @ErrorMsg, 1;
    END

    IF @Criteria IS NULL OR @Criteria = ''
    BEGIN
        SET @ErrorMsg = CONCAT('Search ID ', @SearchId, ' has no criteria');
        THROW 50002, @ErrorMsg, 1;
    END

    IF ISJSON(@Criteria) = 0
    BEGIN
        SET @ErrorMsg = CONCAT('Search ID ', @SearchId, ' has invalid JSON');
        THROW 50003, @ErrorMsg, 1;
    END
END
GO
```

## Migration Scripts

### New Scripts

**045_CreateScalarExtractionFunctions.sql**
- `fn_GetSearchMinimumDt` (scalar)
- `fn_GetSearchMaximumDt` (scalar)
- `fn_GetSearchExtractMisData` (scalar)

**046_CreateSimpleTableFunctions.sql** (inline TVFs)
- `fn_GetSearchWorkOrders`
- `fn_GetSearchItemNumbers`
- `fn_GetSearchProfitCenters`
- `fn_GetSearchWorkCenters`
- `fn_GetSearchOperatorIDs`

**047_CreateComplexTableFunctions.sql** (inline TVFs with OPENJSON...WITH)
- `fn_GetSearchComponentLots`
- `fn_GetSearchPartOperations`

**048_CreateValidateSearchCriteriaProcedure.sql**
- `usp_ValidateSearchCriteria` (stored procedure with THROW)

### Scripts to Delete

Remove obsolete Table Type scripts:
- `033_CreateWorkOrderFilterParameterType.sql`
- `034_CreateItemNumberFilterParameterType.sql`
- `035_CreateProfitCenterFilterParameterType.sql`
- `036_CreateWorkCenterFilterParameterType.sql`
- `037_CreateOperatorFilterParameterType.sql`
- `038_CreateComponentLotFilterParameterType.sql`
- `039_CreateItemOperationMisFilterParameterType.sql`

## C# Changes

### Files to Delete

```
src/JdeScoping.DataAccess/
├── Extensions/
│   └── TableValuedParameterExtensions.cs
├── Models/FilterEntries/
│   ├── WorkOrderFilterEntry.cs
│   ├── ItemNumberFilterEntry.cs
│   ├── ProfitCenterFilterEntry.cs
│   ├── WorkCenterFilterEntry.cs
│   ├── OperatorFilterEntry.cs
│   ├── ComponentLotFilterEntry.cs
│   └── ItemOperationMisFilterEntry.cs
```

### Files to Modify

**`ISearchQueryBuilder.cs`** - New signature:
```csharp
SearchQueryResult BuildSearchQuery(int searchId);
SearchQueryResult BuildMisQuery(int searchId);
SearchQueryResult BuildMisNonMatchQuery(int searchId);
```

**`SqlKataSearchQueryBuilder.cs`** - Generate SQL using functions:
```sql
-- Instead of TVP temp table population:
INSERT INTO #P_WorkOrders SELECT * FROM dbo.fn_GetSearchWorkOrders(@SearchId)
```

**`SearchModel.cs`** - Simplify:
- Remove all `List<*FilterEntry>` properties
- Remove all `*FilterEnabled` computed properties
- Keep: `Id`, `UserName`, `Name`, timestamps, results

**`SearchProcessor.cs`** - Pass `searchId` instead of filter lists

## Test Structure

```
tests/JdeScoping.Database.Tests/
├── Infrastructure/
│   └── DatabaseTestBase.cs
├── Functions/
│   ├── ScalarFunctionTests.cs
│   ├── SimpleTableFunctionTests.cs
│   └── ComplexTableFunctionTests.cs
└── Procedures/
    └── ValidateSearchCriteriaProcedureTests.cs
```

### Test Categories

**Inline TVF Tests (graceful behavior):**
- Valid JSON → correct extraction
- Empty array → empty result
- Missing property → empty result
- Search not found → empty result
- NULL criteria → empty result
- Invalid JSON → empty result
- Bad data types → filtered out (TRY_CONVERT)

**Validation Procedure Tests (strict behavior):**
- Valid search → no error, completes successfully
- Search not found → throws error 50001
- NULL criteria → throws error 50002
- Empty criteria → throws error 50002
- Invalid JSON → throws error 50003

**Edge Cases:**
- Large arrays (1000+ items)
- Special characters in string values
- NULL values within arrays
- Unicode characters
- Nested JSON objects

### Test Infrastructure

Share with `Api.IntegrationTests` via `TestWebApplicationFactory` pattern.

## Documentation Updates

### OpenSpec Specifications
- Update `openspec/specs/data-access/spec.md` - Remove TVP references, add function requirements
- Update `openspec/specs/search-processing/spec.md` - Update query generation
- Update `openspec/specs/database-schema/spec.md` - Document extraction functions

### DOCUMENTATION Folder
- Update architecture diagrams
- Add `DOCUMENTATION/Database/ExtractionFunctions.md`
- Update testing documentation

## Implementation Order

### Phase 1: SQL Functions & Procedure
1. Create `045_CreateScalarExtractionFunctions.sql` (3 scalar functions)
2. Create `046_CreateSimpleTableFunctions.sql` (5 inline TVFs with CTE pattern)
3. Create `047_CreateComplexTableFunctions.sql` (2 inline TVFs with OPENJSON...WITH)
4. Create `048_CreateValidateSearchCriteriaProcedure.sql` (validation procedure)
5. Delete obsolete Table Type scripts (033-039) - keep gaps, don't renumber

### Phase 2: Database Tests
6. Set up `DatabaseTestBase.cs` with xUnit Collection for isolation
7. Write `ScalarFunctionTests.cs`
8. Write `SimpleTableFunctionTests.cs`
9. Write `ComplexTableFunctionTests.cs`
10. Write `ValidateSearchCriteriaProcedureTests.cs`
11. Verify all tests pass

### Phase 3: C# Refactor
12. Update `ISearchQueryBuilder` interface
13. Update `SqlKataSearchQueryBuilder`
14. Update `SearchProcessor`
15. Simplify `SearchModel`
16. Delete `TableValuedParameterExtensions.cs`
17. Delete `FilterEntries/*.cs`
18. Update/delete related tests

### Phase 4: Integration & Verification
19. Run full test suite
20. Fix broken tests
21. Manual end-to-end verification

### Phase 5: Documentation
22. Update OpenSpec specifications
23. Update architecture documentation
24. Add Database.Tests documentation
25. Create ExtractionFunctions.md reference

## Acceptance Criteria

- [ ] All 11 SQL inline TVFs/scalar functions created and working
- [ ] Validation stored procedure created with THROW for errors
- [ ] Inline TVFs return empty results for all edge cases (graceful)
- [ ] Validation procedure throws 50001/50002/50003 for invalid inputs (strict)
- [ ] Table Type scripts (033-039) removed
- [ ] C# TVP code removed (TableValuedParameterExtensions, FilterEntries)
- [ ] Query builder uses SearchId parameter only
- [ ] Database.Tests passing (functions + procedure)
- [ ] Existing integration tests passing
- [ ] Documentation updated