Struct ColumnIdGenerator

pub struct ColumnIdGenerator {
    pub existing: HashMap<String, ColumnId>,
    pub next_column_id: ColumnId,
    pub version_id: TableVersionId,
}

Column ID generator for a new table or a new version of an existing table to alter.

Fields

existing: HashMap<String, ColumnId>

Existing column names and their IDs.

This is used for aligning column IDs between versions (ALTERs). If a column already exists, its ID is reused. Otherwise, a new ID is generated.

For a new table, this is empty.

next_column_id: ColumnId

The next column ID to generate, used for new columns that do not exist in existing.

version_id: TableVersionId

The version ID of the table to be created or altered.

For a new table, this is 0. For altering an existing table, this is the next version ID of the version_id field in the original table catalog.

Implementations

impl ColumnIdGenerator

pub fn new_alter(original: &TableCatalog) -> Self

Creates a new ColumnIdGenerator for altering an existing table.

pub fn new_initial() -> Self

Creates a new ColumnIdGenerator for a new table.

pub fn generate(&mut self, name: &str) -> ColumnId

Generates a new ColumnId for a column with the given name.

pub fn into_version(self) -> TableVersion

Consume this generator and return a TableVersion for the table to be created or altered.

Trait Implementations

impl Debug for ColumnIdGenerator

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

Formats the value using the given formatter.