// FormData_pg_attribute:
// schema-related information for one attribute

typedef struct FormData_pg_attribute
{
  Oid      attrelid;    // OID of reln containing attr
  NameData attname;     // name of attribute
  Oid      atttypid;    // OID of attribute's data type
  int16    attlen;      // attribute length
  int32    attndims;    // # dimensions if array type
  bool     attnotnull;  // can attribute have NULL value
  .....                 // and many other fields
} FormData_pg_attribute;