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sys.ledger_column_history (Transact-SQL)

  • Artikkel

Applies to: SQL Server 2022 (16.x) Azure SQL Database Azure SQL Managed Instance

Captures the cryptographically protected history of operations on columns of ledger tables: adding, renaming, and dropping columns.

For more information on database ledger, see Ledger

Column name Data type Description
object_id int The object ID of the ledger table.
column_id int The column ID of the column in a ledger table.
column_name sysname The name of the column in ledger table. If the operation has changed the column name, this column captures the new column name.
operation_type tinyint The numeric value indicating the type of the operation

0 = CREATE – creating a column as part of creating the table containing the column using CREATE TABLE.
1 = ADD – adding a column in a ledger table, using ALTER TABLE/ADD COLUMN.
2 = RENAME - renaming a column in a ledger table.
3 = DROP - dropping a column in a ledger table.
operation_type_desc nvarchar(60) Textual description of the value of operation_type.
transaction_id bigint A transaction ID that is unique for the database (it corresponds to a transaction ID in the database transaction log).
sequence_number bigint The sequence number of the operation within the transaction.

Permissions

Requires the VIEW LEDGER CONTENT permission.

Examples

Consider the following sequence of operations on ledger tables.

  1. A user creates a ledger table.

    CREATE TABLE [Employees]
(
    EmployeeID INT NOT NULL,
    Salary Money NOT NULL
)
WITH (SYSTEM_VERSIONING = ON, LEDGER = ON);
GO

  2. A user adds a column to the ledger table.

    ALTER TABLE [Employees] ADD Lastname NVARCHAR(256) NULL;

  3. A user renames a column of the ledger table.

    EXEC sp_rename 'dbo.Employees.Lastname', 'Firstname', 'COLUMN';

  4. A user drops a column of the ledger table.

    ALTER TABLE [Employees] DROP COLUMN Firstname;

The below query joins sys.ledger_column_history and sys.database_ledger_transactions to produce the history of changes on ledger table columns, including the time of each and change and the name of the user who triggered it.

SELECT 
t.[principal_name]
, t.[commit_time]
, h.[column_name] AS [column_name]
, h.[operation_type_desc]
FROM sys.ledger_column_history h
JOIN sys.database_ledger_transactions t
ON h.transaction_id = t.transaction_id
ORDER BY t.[commit_time];

See also