MySQL Script to automate creation of audit (history) tables and triggers?
I just wrote this earlier today. It's a select statement working off the information_schema database, which produces the schema for the audit tables and the triggers.
SET GLOBAL group_concat_max_len = 1000;
SET @dbName = "[[[your_db_name_here]]]";
SELECT concat("DROP TABLE IF EXISTS `", @dbName, "`.`", table_data.audit_table, "`;\r",
"CREATE TABLE `", @dbName, "`.`", table_data.audit_table, "`\r",
"(\r",
" `auditAction` ENUM ('INSERT', 'UPDATE', 'DELETE'),\r",
" `auditTimestamp` DATETIME DEFAULT CURRENT_TIMESTAMP,\r",
" `auditId` INT(14) AUTO_INCREMENT,",
column_defs, ",\r"
" PRIMARY KEY (`auditId`),\r",
" INDEX (`auditTimestamp`)\r",
")\r",
" ENGINE = InnoDB;\r\r",
"DROP TRIGGER IF EXISTS `", @dbName, "`.`", table_data.insert_trigger, "`;\r",
"CREATE TRIGGER `", @dbName, "`.`", table_data.insert_trigger, "`\r",
" AFTER INSERT ON `", @dbName, "`.`", table_data.db_table, "`\r",
" FOR EACH ROW INSERT INTO `", @dbName, "`.`", table_data.audit_table, "`\r",
" (`auditAction`,", table_data.column_names, ")\r",
" VALUES\r",
" ('INSERT',", table_data.NEWcolumn_names, ");\r\r",
"DROP TRIGGER IF EXISTS `", @dbName, "`.`", table_data.update_trigger, "`;\r",
"CREATE TRIGGER `", @dbName, "`.`", table_data.update_trigger, "`\r",
" AFTER UPDATE ON `", @dbName, "`.`", table_data.db_table, "`\r",
" FOR EACH ROW INSERT INTO `", @dbName, "`.`", table_data.audit_table, "`\r",
" (`auditAction`,", table_data.column_names, ")\r",
" VALUES\r",
" ('UPDATE',", table_data.NEWcolumn_names, ");\r\r",
"DROP TRIGGER IF EXISTS `", @dbName, "`.`", table_data.delete_trigger, "`;\r",
"CREATE TRIGGER `", @dbName, "`.`", table_data.delete_trigger, "`\r",
" AFTER DELETE ON `", @dbName, "`.`", table_data.db_table, "`\r",
" FOR EACH ROW INSERT INTO `", @dbName, "`.`", table_data.audit_table, "`\r",
" (`auditAction`,", table_data.column_names, ")\r",
" VALUES\r",
" ('DELETE',", table_data.OLDcolumn_names, ");\r\r"
)
FROM (
# This select builds a derived table of table names with ordered and grouped column information in different
# formats as needed for audit table definitions and trigger definitions.
SELECT
table_order_key,
table_name AS db_table,
concat("audit_", table_name) AS audit_table,
concat(table_name, "_inserts") AS insert_trigger,
concat(table_name, "_updates") AS update_trigger,
concat(table_name, "_deletes") AS delete_trigger,
group_concat("\r `", column_name, "` ", column_type ORDER BY column_order_key) AS column_defs,
group_concat("`", column_name, "`" ORDER BY column_order_key) AS column_names,
group_concat("`NEW.", column_name, "`" ORDER BY column_order_key) AS NEWcolumn_names,
group_concat("`OLD.", column_name, "`" ORDER BY column_order_key) AS OLDcolumn_names
FROM
(
# This select builds a derived table of table names, column names and column types for
# non-audit tables of the specified db, along with ordering keys for later order by.
# The ordering must be done outside this select, as tables (including derived tables)
# are by definition unordered.
# We're only ordering so that the generated audit schema maintains a resemblance to the
# main schema.
SELECT
information_schema.tables.table_name AS table_name,
information_schema.columns.column_name AS column_name,
information_schema.columns.column_type AS column_type,
information_schema.tables.create_time AS table_order_key,
information_schema.columns.ordinal_position AS column_order_key
FROM information_schema.tables
JOIN information_schema.columns
ON information_schema.tables.table_name = information_schema.columns.table_name
WHERE information_schema.tables.table_schema = @dbName
AND information_schema.columns.table_schema = @dbName
AND information_schema.tables.table_name NOT LIKE "audit\_%"
) table_column_ordering_info
GROUP BY table_name
) table_data
ORDER BY table_order_key
INTO OUTFILE "[[[your_output_file]]]"