Enum Column 

pub enum Column<'a> {
    Add(&'a Column),
    Drop(&'a Column),
    Alter {
        previous: &'a Column,
        next: &'a Column,
    },
}

A single column-level change between two table versions.

Computed by Column::diff.

Variants

Add(&'a Column)

A new column was added.

Drop(&'a Column)

An existing column was removed.

Alter

A column was modified (name, type, nullability, or other property changed).

Fields

previous: &'a Column

The column definition before the change.

next: &'a Column

The column definition after the change.

Implementations

impl<'a> Column<'a>

pub fn diff( cx: &Context<'a>, previous: &'a [Column], next: &'a [Column], ) -> Vec<Self>

Computes the diff between two column slices.

Uses Context to resolve rename hints. Columns matched by name (or by rename hint) are compared field-by-field; unmatched columns in previous become drops, and unmatched columns in next become adds.

Examples

use toasty_core::schema::{db, diff};

let previous = db::Schema::default();
let next = db::Schema::default();
let hints = diff::RenameHints::new();
let cx = diff::Context::new(&previous, &next, &hints);
assert!(diff::Column::diff(&cx, &[], &[]).is_empty());