Struct ColumnMapping 

pub struct ColumnMapping {
    pub column_name: String,
    pub expression: Option<String>,
}

Defines how a column receives its value during insertion.

Column mappings allow you to:

• Insert values directly from the inserter stream
• Compute values using SQL expressions
• Use server-side functions like NOW() or DEFAULT

Example

use hyperdb_api::ColumnMapping;

// Simple column - insert value directly
let id_col = ColumnMapping::new("id");

// Column with expression - computed value
let created_at = ColumnMapping::with_expression("created_at", "NOW()");
let full_name = ColumnMapping::with_expression("full_name", "first_name || ' ' || last_name");

Fields

column_name: String

The name of the target column.

expression: Option<String>

Optional SQL expression. If None, the value is inserted directly.

Implementations

impl ColumnMapping

pub fn new(column_name: impl Into<String>) -> Self

Creates a column mapping for direct value insertion.

The column will receive values directly from the inserter.

pub fn with_expression( column_name: impl Into<String>, expression: impl Into<String>, ) -> Self

Creates a column mapping with a SQL expression.

The column value will be computed using the given SQL expression. The expression can reference other columns or use SQL functions.

Arguments

• column_name - The name of the target column.
• expression - A SQL expression to compute the column value.

Example

use hyperdb_api::ColumnMapping;

// Use current timestamp
let created = ColumnMapping::with_expression("created_at", "NOW()");

// Compute from other columns
let total = ColumnMapping::with_expression("total", "quantity * price");

pub fn column_name(&self) -> &str

Returns the column name.

pub fn expression(&self) -> Option<&str>

Returns the SQL expression, if any.

pub fn is_direct(&self) -> bool

Returns true if this is a direct value mapping (no expression).

Trait Implementations

impl Clone for ColumnMapping

fn clone(&self) -> ColumnMapping

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ColumnMapping

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

Formats the value using the given formatter.