Net4x.DapperLibrary.Oracle 1.9.9

DapperLibrary.SqlServer

# DapperLibrary.Oracle

Oracle provider integration for DapperLibrary. This project provides an Oracle-specific `DapperContext` implementation, a provider factory and Oracle-specific database model and type mappings.

## Purpose

Provide Oracle engine-specific behavior while keeping the DapperLibrary public API consistent across providers. The assembly includes:

- `OracleDapperContext` � a `DapperContext` configured for Oracle (Oracle Managed Data Access).
- `OracleProviderFactory` � configures parameter handling, adapter event forwarding and the `DatabaseModel` factory for Oracle.
- `OracleDatabaseModel`, `OracleDatabaseModelTypes` and `OracleDatabaseEnumTypes` � identifier delimiters, statement terminator, parameter naming and Oracle-specific SQL type strings and enum mappings.

## Key types

- `OracleDapperContext`
  - Derives from `DapperContext` and initializes the context with `OracleProviderFactory` and configuration from `DapperConfigurationManager`.
  - Static helpers `Use`, `Use(IContextCreator)`, `Use(string, string)` and `UseOnce` integrate with `DapperContextFactory` and set Oracle-specific defaults:
    - `DatabaseModel.IdentityInitializer = "GENERATED BY DEFAULT AS IDENTITY"` (Oracle identity/sequence semantics)
    - `DatabaseModel.FormatDatetimeAsString = dateTime => $"TO_DATE('{dateTime:yyyy-MM-dd HH:mm:ss}', 'YYYY-MM-DD HH24:MI:SS')"` for generating Oracle-compatible datetime literals.

- `OracleProviderFactory`
  - Inherits from `ProviderFactoryBase` and wraps `OracleClientFactory.Instance` (Oracle Managed Data Access).
  - Sets `ParameterModel.ParameterPrefix = ":"` and `ParameterModel.AddIndex = true` and installs `PrepareCommandParameters` delegate.
  - Creates `OracleDataAdapter` instances and forwards `RowUpdating`/`RowUpdated` events.

- `OracleDatabaseModel` and related types
  - Identifier delimiters: `"` (double-quote).
  - Statement terminator: `;`.
  - Parameter prefix: `:`.
  - Type mappings reflect Oracle types (for example `RAW(16)` for GUID, `CLOB` for text, `NUMBER`/`NUMBER(19)` for numerics, `BLOB` for binary).

## Usage examples

Create and use an `OracleDapperContext` directly:

```csharp
using var context = new OracleDapperContext();
// use context.Operations / context.Schema / context.SaveDataTable etc.
```

Register a context creator in bootstrap code:

```csharp
OracleDapperContext.Use();

// or bind an explicit connection string and provider name
OracleDapperContext.UseOnce(connectionString, providerName);
```

When creating contexts via the helpers, the database model will be pre-configured with Oracle-friendly defaults for identity/sequence behavior and datetime formatting.

## Multi-targeting & client compatibility

- This project targets .NET Standard 2.1 in the workspace and depends on Oracle Managed Data Access (`Oracle.ManagedDataAccess.Client`) which has specific compatibility constraints. Ensure the consuming application references the appropriate Oracle ManagedDataAccess package compatible with its target framework.
- The DapperLibraries solution includes conditional compilation across projects to allow building provider-specific assemblies for a variety of .NET Framework and modern .NET targets.

## Synchronous vs asynchronous behavior

- `Oracle.ManagedDataAccess` provides asynchronous APIs in supported versions; DapperLibrary exposes both synchronous and `Async` suffixed methods (`GetDataReaderAsync`, `GetDataTableAsync`, `SetDataAsync`, etc.).
- Prefer asynchronous APIs in server or I/O-bound applications. If running on older framework targets or using provider versions without full async support, synchronous methods remain available and are safe to use.

## Events and adapter behavior

- `OracleProviderFactory.CreateDataAdapter` attaches to `RowUpdating`/`RowUpdated` events of `OracleDataAdapter` and forwards them via the provider factory so consumer code can hook into adapter lifecycle when using `SaveDataTable` and similar operations.

## Notes and best practices

- Use `WithConnection` overloads when executing operations against a different named connection for a single call to avoid race conditions around `ConnectionStringToRead`.
- Prefer the `Use` / `UseOnce` helpers to ensure consistent Oracle-specific configuration across created contexts.
- Rely on the schema helpers (`IDapperContext.Schema`) and the library's caching for efficient metadata inspection.

For implementation details, consult the source files under `DbContexts` and `OracleProviderFactory`.