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docs/ai/DataPRO/UnitTest/DatabaseUnitTesting/Utilities.md

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+---
+source_files:
+  - DataPRO/UnitTest/DatabaseUnitTesting/Utilities/ObjectsToCompare.cs
+  - DataPRO/UnitTest/DatabaseUnitTesting/Utilities/DatabaseAdapter.cs
+  - DataPRO/UnitTest/DatabaseUnitTesting/Utilities/DatabaseComparer.cs
+generated_at: "2026-04-17T15:54:33.868933+00:00"
+model: "zai-org/GLM-5-FP8"
+schema_version: 1
+sha256: "f31068a46fa2e835"
+---
+
+# Database Unit Testing Utilities Documentation
+
+## 1. Purpose
+
+This module provides internal utilities for comparing database objects between two databases, primarily designed to support database unit testing scenarios. It enables snapshot creation/management, object-level data comparison, and difference reporting. The three classes work together: `ObjectsToCompare` serves as a configuration container for comparison pairs, `DatabaseAdapter` provides low-level database operations (including snapshot management), and `DatabaseComparer` orchestrates the actual data comparison logic using set-based SQL operations.
+
+---
+
+## 2. Public Interface
+
+### ObjectsToCompare (internal class)
+
+A configuration container that holds metadata about two database objects to be compared.
+
+**Constructor:**
+```csharp
+public ObjectsToCompare(string schema1Name, string object1Name, string schema2Name, string object2Name)
+```
+Initializes a new comparison pair with schema and object names for both sides.
+
+**Properties:**
+| Property | Type | Description |
+|----------|------|-------------|
+| `Schema1Name` | `string` | Schema name of the first object |
+| `Object1Name` | `string` | Name of the first object |
+| `Schema2Name` | `string` | Schema name of the second object |
+| `Object2Name` | `string` | Name of the second object |
+| `Qualified1` | `string` | Returns `_schema1Name + "." + _object1Name` |
+| `Qualified2` | `string` | Returns `_schema2Name + "." + _object2Name` |
+| `ColumnsToIgnore` | `IEnumerable<string>` | Returns the list of columns to exclude from comparison |
+
+**Methods:**
+```csharp
+public void AddColumnToIgnore(string columnName)
+```
+Adds a column name to the internal `_columnsToIgnore` list.
+
+---
+
+### DatabaseAdapter (internal class)
+
+Provides low-level database operations including snapshot management.
+
+**Constructor:**
+```csharp
+internal DatabaseAdapter(SqlConnection connection)
+```
+Stores the connection and opens it if currently closed.
+
+**Methods:**
+```csharp
+internal bool IsSnapshot(string name)
+```
+Queries `sys.databases` to check if the named database is a snapshot (checks if `source_database_id` is not null/DBNull).
+
+```csharp
+internal void UseDatabase(string databaseName)
+```
+Executes `USE [databaseName]` to switch the connection context.
+
+```csharp
+internal void CreateSnapshot(string databaseName, string snapshotName)
+```
+Creates a database snapshot with the file stored at `C:\Temp\[snapshotName]`.
+
+```csharp
+internal void DropSnapshot(string snapshotName)
+```
+Drops the specified snapshot. Throws `ArgumentException` if the named database is not a snapshot.
+
+---
+
+### DatabaseComparer (internal class)
+
+Orchestrates comparison