Struct SchemaMutations 

pub struct SchemaMutations {
    pub alter_column_type: bool,
    pub alter_column_properties_atomic: bool,
}

The database’s capabilities to mutate the schema (tables, columns, indices).

Used by the migration generator to decide how to express each column change. alter_column_type gates whether an in-place ALTER COLUMN is possible at all — SQLite has it set to false, and a type change there triggers a full table rebuild (create new table, copy rows, drop old). alter_column_properties_atomic decides whether several column-property changes (rename, retype, NOT NULL, default) collapse into one statement or emit one per property. MySQL sets both to true; PostgreSQL alters in place but requires one statement per property.

Pre-built configurations: SQLITE, POSTGRESQL, MYSQL, DYNAMODB.

Examples

Access through Capability::schema_mutations:

use toasty_core::driver::Capability;

let cap = &Capability::POSTGRESQL;
assert!(cap.schema_mutations.alter_column_type);
assert!(!cap.schema_mutations.alter_column_properties_atomic);

Fields

alter_column_type: bool

Whether the database can change the type of an existing column.

alter_column_properties_atomic: bool

Whether the database can change name, type and constraints of a column all withing a single statement.

Implementations

impl SchemaMutations

pub const SQLITE: Self

SQLite schema mutation capabilities. SQLite cannot alter column types.

pub const POSTGRESQL: Self

PostgreSQL schema mutation capabilities. Supports altering column types but not atomically changing multiple column properties.

pub const MYSQL: Self

MySQL schema mutation capabilities. Supports altering column types and atomically changing multiple column properties in a single statement.

pub const DYNAMODB: Self

DynamoDB schema mutation capabilities. Migrations are not currently supported.

Trait Implementations

impl Debug for SchemaMutations

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

Formats the value using the given formatter.