---
source_files:
  - Common/DTS.Common.Storage/Classes/NoDBAccessException.cs
  - Common/DTS.Common.Storage/Classes/DigitalInputSettings.cs
  - Common/DTS.Common.Storage/Classes/DbTypeAttr.cs
  - Common/DTS.Common.Storage/Classes/DAS.cs
  - Common/DTS.Common.Storage/Classes/MMETables.cs
generated_at: "2026-04-16T11:53:30.528055+00:00"
model: "zai-org/GLM-5-FP8"
schema_version: 1
sha256: "ad177a41b5582582"
---

# DTS.Common.Storage Module Documentation

## 1. Purpose

This module provides data storage schema definitions, custom attributes, and exception handling for the DTS storage layer. It defines database table structures, field enumerations, and hardware prototype identifiers used across the system for data acquisition systems (DAS), digital input settings, and measurement/monitoring equipment (MME) management. The module serves as a central schema contract between the database layer and consuming application code.

---

## 2. Public Interface

### NoDBAccessException
**Signature:** `public class NoDBAccessException : Exception`

**Constructor:**
```csharp
public NoDBAccessException(Exception ex)
```

Wraps an existing exception to indicate a database access failure. Preserves the original exception's message and stack trace by passing it as the inner exception.

---

### DigitalInputSettings
**Signature:** `public class DigitalInputSettings`

Defines the schema for digital input configuration storage.

| Member | Type | Description |
|--------|------|-------------|
| `Table` | `const string` | Value: `"tblDigitalInputSetting"` - the database table name |
| `Fields` | `enum` | Enumeration of column names: `SettingName`, `SettingMode`, `ScaleMultiplier`, `LastModified`, `LastModifiedBy`, `SensorId`, `UserValue1`, `UserValue2`, `UserValue3`, `UserTags` |

---

### DbTypeAttr
**Signature:** `public class DbTypeAttr : Attribute`

A custom attribute for annotating enum members with database type information.

| Member | Signature | Description |
|--------|-----------|-------------|
| `DbType` | `public string DbType { get; private set; }` | The database type string |
| `DbTypeAttr(string attr)` | `internal` constructor | Creates an instance with the specified type. Internal visibility restricts instantiation to this assembly. |
| `GetDbType(object o)` | `public static string GetDbType(object o)` | Uses reflection to retrieve the `DbTypeAttr` value from an object's member. Returns `null` if the object is null, has no members, or lacks the attribute. |

---

### DAS
**Signature:** `public class DAS`

Defines the schema for Data Acquisition System hardware configuration.

**Constants:**

| Member | Value |
|--------|-------|
| `Table` | `"tblDAS"` |
| `TableDASChannels` | `"tblDASChannels"` |

**Prototype Constants (all `const string`):**
- `SLICE1_PROTOTYPE`, `SLICEPRO_PROTOTYPE`, `PROTOTYPE_POSITION`
- `SLICE1_5PROTOTYPE`, `G5_VDSPROTOTYPE`, `G5_IPORTPROTOTYPE`
- `TDASPRO_8MRack`, `TDASPRO_4MRack`, `ECM_PROTOTYPE`
- `SLE_PROTOTYPE`, `SDB_PROTOTYPE`, `Slice_NanoPROTOTYPE`, `Slice_MicroPROTOTYPE`
- `SLICEPRODIM_PROTOTYPE`, `SLICEPROSLD_PROTOTYPE`, `SLICEPROTOM_PROTOTYPE`
- `SLICEPROSLT_PROTOTYPE`, `SLICEPROSIM_PROTOTYPE`, `SLICEPROSLS_PROTOTYPE`
- `SLICE1_5_MicroPROTOTYPE`, `G5_INDUMMYPROTOTYPE`, `SG5_PROTOTYPE`
- `TDASPRO_LabRack`, `SLICE6_PROTOTYPE`, `SLICE6DB_PROTOTYPE`

**Enums:**

| Enum | Fields |
|------|--------|
| `Fields` | `SerialNumber`, `Type`, `MaxModules`, `MaxMemory`, `MaxSampleRate`, `MinSampleRate`, `FirmwareVersion`, `CalDate`, `ProtocolVersion`, `LastModified`, `LastModifiedBy`, `Version`, `LocalOnly`, `LastUsed`, `LastUsedBy`, `Connection`, `Channels`, `Position`, `ChannelTypes`, `Reprogramable`, `Reconfigurable`, `IsModule` |
| `DASChannelFields` | `HardwareId`, `ChannelIdx`, `SupportedBridges`, `SupportedExcitations`, `DASDisplayOrder`, `LocalOnly`, `SupportedDigitalInputModes`, `SupportedSquibFireModes`, `SupportedDigitalOutputModes`, `ModuleSerialNumber`, `ModuleArrayIndex` |

---

### MMETables
**Signature:** `public class MMETables`

Defines schemas for Measurement/Monitoring Equipment reference data tables.

**Legacy Field Name Constants:**

| Constant | Comment |
|----------|---------|
| `MyType` | Exported in versions up to 1.3.496; replaced by `"CustomChannelType"` |
| `CustomChannelType` | Exported in versions 1.3.498 - 1.3.515; replaced by `"TYPE"` |
| `Id` | Exported in versions up to 1.3.515; replaced by `"ID"` |

**Table Constants and Associated Enums:**

| Table Constant | Enum | Notable Fields |
|----------------|------|----------------|
| `MMEPossibleChannelsTable` (`"tblMMEPossibleChannels"`) | `MMEPossibleChannelsFields` | Fields decorated with `[CustomChannelFieldSize(n)]` attribute: `TEST_OBJECT`, `POSITION`, `TRANS_MAIN_LOC`, `FINE_LOC_1/2/3`, `PHYSICAL_DIMENSION`, `DIRECTION`, `DEFAULT_FILTER_CLASS`, `TEXT_L1/L2`, `REMARKS`, `SORTKEY`, `PICTURE_SHORTNAME`, `LAST_CHANGE`, `LAST_CHANGE_TEXT`, `HISTORY` |
| `MMEDirectionsTable` (`"tblMMEDirections"`) | `MMEDirectionsFields` | `s_GUID`, `DIRECTION`, `TEXT_L1/L2`, `VERSION`, `DATE`, `REMARKS`, `EXPIRED`, `SORTKEY`, `LAST_CHANGE`, `LAST_CHANGE_TEXT`, `HISTORY` |
| `MMEFilterClassesTable` (`"tblMMEFilterClasses"`) | `MMEFilterClassesFields` | `s_GUID`, `FILTER_CLASS`, standard metadata fields |
| `MMEFineLocations1Table`/`2Table`/`3Table` | `MMEFineLocations1Fields`/`2Fields`/`3Fields` | `s_GUID`, `FINE_LOC_1/2/3`, standard metadata fields |
| `MMEPhysicalDimensions` (`"tblMMEPhysicalDimensions"`) | `MMEPhysicalDimensionFields` | `s_GUID`, `PHYSICAL_DIMENSION`, `DEFAULT_UNIT`, dimension exponents (`LENGTH_EXP`, `TIME_EXP`, `MASS_EXP`, `ELECTRIC_CURRENT_EXP`, `TEMPERATURE_EXP`, `LUMINOUS_INTENSITY_EXP`, `AMOUNT_OFSUBSTANCE_EXP`) |
| `MMEPositionsTable` (`"tblMMEPositions"`) | `MMEPositionsFields` | `s_GUID`, `POSITION`, standard metadata fields |
| `MMETestObjectsTable` (`"tblMMETestObjects"`) | `MMETestObjectsFields` | `s_GUID`, `TEST_OBJECT`, standard metadata fields |
| `MMEMainLocationTable` (`"tblMMEMainLocations"`) | `MMEMainLocationsFields` | `s_GUID`, `TYPE`, `TRANS_MAIN_LOC`, `PICTURE_SHORTNAME`, standard metadata fields |

---

## 3. Invariants

- **DbTypeAttr construction**: The `DbTypeAttr` constructor is `internal`, ensuring attributes can only be created within this assembly.
- **Field name stability**: The `Fields` enums use implicit integer values (0, 1, 2, ...). Adding new fields to the end of an enum preserves existing values; inserting in the middle would break compatibility.
- **Legacy field name compatibility**: The constants `MyType`, `CustomChannelType`, and `Id` in `MMETables` exist to support data migration from older schema versions (pre-1.3.515).
- **Null safety in GetDbType**: The `DbTypeAttr.GetDbType()` method handles null inputs and missing attributes gracefully by returning `null` rather than throwing.

---

## 4. Dependencies

**This module depends on:**
- `System` namespace (for `Exception`, `Attribute`, reflection types)
- `System.Reflection.MemberInfo` (used in `DbTypeAttr.GetDbType`)
- `CustomChannelFieldSizeAttribute` (referenced in `MMETables.MMEPossibleChannelsFields` but **not defined in these source files**)

**Consumers (inferred):**
- Any module that reads/writes to the defined database tables (`tblDigitalInputSetting`, `tblDAS`, `tblDASChannels`, `tblMME*` tables)
- Hardware detection/configuration logic that references DAS prototype constants
- Database migration tooling that needs to handle legacy field names

---

## 5. Gotchas

1. **Legacy field name migration**: The `MMETables` class contains three legacy field name constants (`MyType`, `CustomChannelType`, `Id`) with explicit version comments. Code reading from or migrating older databases must account for these renamed fields.

2. **Missing attribute definition**: `MMETables.MMEPossibleChannelsFields` uses `[CustomChannelFieldSize(n)]` attribute on multiple fields, but this attribute is not defined in the provided source files. Its location and behavior are unknown.

3. **Reflection performance**: `DbTypeAttr.GetDbType()` performs reflection on every call. In performance-critical paths, consider caching results.

4. **NoDBAccessException loses original type**: Wrapping an exception in `NoDBAccessException` obscures the original exception type. Catch blocks looking for specific exception types (e.g., `SqlException`) will not match.

5. **Typo in enum field**: `MMEPhysicalDimensionFields.AMOUNT_OFSUBSTANCE_EXP` appears to have a missing space in "OFSUBSTANCE" — this may be intentional (matching database column name) or a typo that is now persisted in the schema.