Struct SchemaDiff 

pub struct SchemaDiff {
    pub entries: Vec<DiffEntry>,
}

Represents the difference between two schemas.

The diff algorithm compares the Rust schema (source of truth) against the database schema (current state) to produce a set of changes. The comparison is done at two levels:

1. Table level: Find tables that exist in Rust but not DB (CREATE), or exist in DB but not Rust (DROP, except forge_ internal tables).

2. Column level: For tables in both, compare fields:

   • Field in Rust but not DB → ADD COLUMN
   • Field in DB but not Rust → DROP COLUMN
   • Field in both but different type → ALTER COLUMN TYPE

The algorithm is intentionally simple and doesn’t handle:

• Column renames (seen as DROP + ADD)
• Index changes (handled separately)
• Complex type migrations (require manual migration)

This is by design: automatic migrations are for development convenience. Production deployments should use explicit migration files.

Fields

entries: Vec<DiffEntry>

Changes to be applied.

Implementations

impl SchemaDiff

pub fn new() -> Self

Create an empty diff.

pub fn from_comparison( rust_tables: &[TableDef], db_tables: &[DatabaseTable], ) -> Self

Compare a Rust schema to a database schema.

pub fn is_empty(&self) -> bool

Check if there are any changes.

pub fn to_sql(&self) -> Vec<String>

Get all SQL statements.

Trait Implementations

impl Clone for SchemaDiff

fn clone(&self) -> SchemaDiff

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SchemaDiff

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for SchemaDiff

fn default() -> Self

Returns the “default value” for a type.