!--a11y-->
alter_table_statement 
<
alter_table_statement> ::=
ALTER TABLE <table_name> <add_definition>
| ALTER TABLE <table_name> <drop_definition>
| ALTER TABLE <table_name> <alter_definition>
| ALTER TABLE <table_name> <column_change_definition>
| ALTER TABLE <table_name> <modify_definition>
| ALTER TABLE <table_name> <referential_constraint_definition>
| ALTER TABLE <table_name> DROP FOREIGN KEY <referential_constraint_name>
| ALTER TABLE <table_name> <sample_definition>
