Method try_parse

src/sql-server-util/src/cdc.rs:734–793

Parse the provided [`tiberius::Row`] to determine what [`Operation`] occurred. See .

(data: tiberius::Row)

    ///
    /// See <https://learn.microsoft.com/en-us/sql/relational-databases/system-functions/cdc-fn-cdc-get-all-changes-capture-instance-transact-sql?view=sql-server-ver16#table-returned>.
    fn try_parse(data: tiberius::Row) -> Result<(Lsn, Self), SqlServerError> {
        static START_LSN_COLUMN: &str = "__$start_lsn";
        static OPERATION_COLUMN: &str = "__$operation";
        static SEQVAL_COLUMN: &str = "__$seqval";

        let lsn: &[u8] = data
            .try_get(START_LSN_COLUMN)
            .map_err(|e| CdcError::RequiredColumn {
                column_name: START_LSN_COLUMN,
                error: e.to_string(),
            })?
            .ok_or_else(|| CdcError::RequiredColumn {
                column_name: START_LSN_COLUMN,
                error: "got null value".to_string(),
            })?;
        let operation: i32 = data
            .try_get(OPERATION_COLUMN)
            .map_err(|e| CdcError::RequiredColumn {
                column_name: OPERATION_COLUMN,
                error: e.to_string(),
            })?
            .ok_or_else(|| CdcError::RequiredColumn {
                column_name: OPERATION_COLUMN,
                error: "got null value".to_string(),
            })?;
        let seqval: &[u8] = data
            .try_get(SEQVAL_COLUMN)
            .map_err(|e| CdcError::RequiredColumn {
                column_name: SEQVAL_COLUMN,
                error: e.to_string(),
            })?
            .ok_or_else(|| CdcError::RequiredColumn {
                column_name: SEQVAL_COLUMN,
                error: "got null value".to_string(),
            })?;

        let lsn = Lsn::try_from(lsn).map_err(|msg| SqlServerError::InvalidData {
            column_name: START_LSN_COLUMN.to_string(),
            error: msg,
        })?;
        let seqval = Lsn::try_from(seqval).map_err(|msg| SqlServerError::InvalidData {
            column_name: SEQVAL_COLUMN.to_string(),
            error: msg,
        })?;

        let operation = match operation {
            1 => Operation::Delete(data),
            2 => Operation::Insert(data),
            3 => Operation::UpdateOld(seqval, data),
            4 => Operation::UpdateNew(seqval, data),
            other => {
                return Err(SqlServerError::InvalidData {
                    column_name: OPERATION_COLUMN.to_string(),
                    error: format!("unrecognized operation {other}"),
                });
            }
        };