Struct Column 

#[non_exhaustive]
pub struct Column {
    pub name: String,
    pub index: usize,
    pub type_name: String,
    pub nullable: bool,
    pub max_length: Option<u32>,
    pub precision: Option<u8>,
    pub scale: Option<u8>,
    pub collation: Option<Collation>,
}

Column metadata describing a result set column.

This struct is marked #[non_exhaustive] to allow adding new fields in future versions without breaking semver compatibility. Use Column::new() or builder methods to construct instances.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

name: String

Column name.

index: usize

Column index (0-based).

type_name: String

SQL type name (e.g., “INT”, “NVARCHAR”).

nullable: bool

Whether the column allows NULL values.

max_length: Option<u32>

Maximum length for variable-length types.

precision: Option<u8>

Precision for numeric types.

scale: Option<u8>

Scale for numeric types.

collation: Option<Collation>

Collation for string types (VARCHAR, CHAR, TEXT).

Used for proper encoding/decoding of non-Unicode string data. When present, enables collation-aware decoding that correctly handles locale-specific ANSI encodings (e.g., Shift_JIS, GB18030).

Implementations

impl Column

pub fn new( name: impl Into<String>, index: usize, type_name: impl Into<String>, ) -> Self

Create a new column with basic metadata.

pub fn with_nullable(self, nullable: bool) -> Self

Set whether the column is nullable.

pub fn with_max_length(self, max_length: u32) -> Self

Set the maximum length.

pub fn with_precision_scale(self, precision: u8, scale: u8) -> Self

Set precision and scale for numeric types.

pub fn with_collation(self, collation: Collation) -> Self

Set the collation for string types.

Used for proper encoding/decoding of non-Unicode string data (VARCHAR, CHAR, TEXT).

pub fn encoding_name(&self) -> &'static str

Get the encoding name for this column’s collation.

Returns the name of the character encoding used for this column’s data, or “unknown” if the collation is not set or the encoding feature is disabled.

Examples

• "Shift_JIS" - Japanese encoding (LCID 0x0411)
• "GB18030" - Simplified Chinese (LCID 0x0804)
• "UTF-8" - SQL Server 2019+ UTF-8 collation
• "windows-1252" - Latin/Western European (LCID 0x0409)
• "unknown" - No collation or unsupported encoding

pub fn is_utf8_collation(&self) -> bool

Check if this column uses UTF-8 encoding.

Returns true if the column has a SQL Server 2019+ UTF-8 collation, which is indicated by bit 27 (0x0800_0000) being set in the LCID.

pub fn to_type_info(&self) -> TypeInfo

Convert column metadata to TDS TypeInfo for decoding.

Maps type names to TDS type IDs and constructs appropriate TypeInfo.

Trait Implementations

impl Clone for Column

fn clone(&self) -> Column

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Column

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

Formats the value using the given formatter.