alterColumnDeleteRule method
Implementation
List<String> alterColumnDeleteRule(SchemaTable table, SchemaColumn column) {
var allCommands = <String>[];
allCommands.add(
"ALTER TABLE ONLY ${table.name} DROP CONSTRAINT ${_foreignKeyName(table.name, column)}");
allCommands.addAll(_addConstraintsForColumn(table.name, column));
return allCommands;
}