Module db 

Database-level (table/column-oriented) schema definitions. Database-level schema definitions.

This module represents what the database sees: tables, columns, indices, primary keys, storage types, and migrations. It is the counterpart to the application-level schema in [super::app], with the two layers connected by the [super::mapping] module.

Key types

Type	Purpose
Schema	Collection of all tables in a database
Table	A single database table with columns, indices, and a primary key
[Column]	A column within a table, including its name, type, and constraints
[Index]	A database index over one or more columns
[Type]	Database storage type (e.g. Integer(4), Text, VarChar(255))
[PrimaryKey]	The primary key definition for a table
[Migration]	A SQL migration generated from a schema diff

Schema diffing

The module provides diff types ([SchemaDiff], [TablesDiff], [ColumnsDiff], [IndicesDiff]) that compare two schema versions and produce a list of structural changes. [RenameHints] lets callers indicate which items were renamed (rather than dropped and recreated).

Structs

AppliedMigration

Metadata about a migration that has already been applied to a database.

Column

A column in a database table.

ColumnId

Uniquely identifies a column within a schema.

ColumnsDiff

The set of differences between two column lists.

DiffContext

Shared context passed to all diff computations.

Index

A database index over one or more columns of a table.

IndexColumn

A single column entry within an Index.

IndexId

Uniquely identifies an index within a schema.

IndicesDiff

The set of differences between two index lists.

PrimaryKey

The primary key definition for a database table.

RenameHints

Hints that tell the diff algorithm which schema items were renamed.

Schema

The complete database-level schema: a collection of tables.

SchemaDiff

The top-level diff between two database schemas.

Table

A database table with its columns, primary key, and indices.

TableId

Uniquely identifies a table within a Schema.

TablesDiff

The set of differences between two table lists.

Enums

ColumnsDiffItem

A single change detected between two column lists.

IndexOp

The comparison operation used by an index column.

IndexScope

Scope of an index column, relevant for distributed databases.

IndicesDiffItem

A single change detected between two index lists.

Migration

A database migration generated from a SchemaDiff by a driver.

TablesDiffItem

A single change detected between two table lists.

Type

Database-level storage types representing how values are stored in the target database.