PostgreSQL:

SECURITY LABEL

SECURITY LABEL [ FOR provider ] ON
{
TABLE object_name |
COLUMN table_name.column_name |
AGGREGATE agg_name (agg_type [, ...] ) |
DOMAIN object_name |
FOREIGN TABLE object_name
FUNCTION function_name ( [ [ argmode ] [ argname ] argtype [, ...] ] ) |
LARGE OBJECT large_object_oid |
[ PROCEDURAL ] LANGUAGE object_name |
SCHEMA object_name |
SEQUENCE object_name |
TYPE object_name |
VIEW object_name
} IS 'label'

Example

SECURITY LABEL FOR selinux ON TABLE mytable IS 'system_u:object_r:sepgsql_table_t:s0';