DatabaseMigrationScripts

Purpose

This module provides utilities for reading embedded resources (e.g., SQL migration scripts) from a .NET assembly’s manifest resources. It exists to simplify access to versioned, compiled-in migration files without requiring external file system dependencies, enabling reliable deployment of database schema changes across environments.

Public Interface

static StreamReader GetStream(Assembly assembly, string name)
Searches the manifest resources of the given assembly for a resource whose name ends with name (case-sensitive substring match), and returns a StreamReader for the first match. Returns null if no matching resource is found.
Note: Caller is responsible for disposing the StreamReader.
static string GetString(Assembly assembly, string name)
Reads the full content of the resource matching name (via GetStream) from the specified assembly and returns it as a string. Closes the StreamReader internally. Returns null if no matching resource is found.
static string GetString(string name)
Overload of GetString that uses the assembly containing the EmbeddedResource type itself (typeof(EmbeddedResource).Assembly) as the source. Behaves identically to GetString(assembly, name) otherwise.

Invariants

Resource matching is performed via EndsWith(name) on the full manifest resource name (e.g., "MyApp.Migrations.V1_0_0.sql" matches for name = "V1_0_0.sql").
Only the first matching resource (by enumeration order) is used—no error is raised if multiple resources match.
GetString(Assembly, string) and GetString(string) return null if no matching resource exists (not an exception).
The StreamReader returned by GetStream must be explicitly closed/disposed by the caller to avoid resource leaks.
GetString methods assume the resource content is text-encoded (UTF-8 or system default encoding, per StreamReader default behavior).

Dependencies

Depends on:
- System.IO (StreamReader, Stream)
- System.Reflection.Assembly (for GetManifestResourceNames, GetManifestResourceStream)
Depended on by:
- Presumably database migration orchestration logic (e.g., a MigrationRunner class) that loads .sql files from embedded resources.
- Inferred: Other types in the DatabaseMigrationScripts namespace (not visible here) likely consume EmbeddedResource to retrieve migration scripts.

Gotchas

Substring matching is ambiguous: A request for "V1.sql" could match "V1.sql", "Old/V1.sql", or "Backup_V1.sql"—only the first match in GetManifestResourceNames() order is used. This may cause unexpected behavior if resource naming is not strictly controlled.
No encoding specification: StreamReader uses default encoding (typically UTF-8 without BOM on .NET Core/.NET 5+, but system default on .NET Framework), which may cause issues if migration files contain non-ASCII characters and were authored with a different encoding.
Resource enumeration order is undefined: GetManifestResourceNames() does not guarantee consistent ordering across builds or platforms, so multiple matching resources may yield non-deterministic results.
No validation of resource existence before ReadToEnd(): If GetStream returns null, GetString will throw a NullReferenceException when calling sr.ReadToEnd(). This is a critical bug: GetString(Assembly, string) lacks null-checking on sr.
EmbeddedResource() constructor is private but unused: The class is never instantiated (all members are static), but the empty constructor serves no functional purpose.
No support for binary resources: Designed exclusively for text-based resources; binary files would require a different approach.

Note: The NullReferenceException risk in GetString(Assembly, string) when GetStream returns null is a likely source of runtime failures and should be addressed.

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