code: func PgOpclassByOpcmethodOpcnameOpcnamespace(db XODB, opcmethod pgtypes.Oid, opcname pgtypes.Name, opcnamespace pgtypes.Oid) (*PgOpclass, error) {
  	var err error
  
  	// sql query
  	const sqlstr = `SELECT ` +
  		`tableoid, cmax, xmax, cmin, xmin, oid, ctid, opcmethod, opcname, opcnamespace, opcowner, opcfamily, opcintype, opcdefault, opckeytype ` +
  		`FROM pg_catalog.pg_opclass ` +
  		`WHERE opcmethod = $1 AND opcname = $2 AND opcnamespace = $3`
  
  	// run query
  	XOLog(sqlstr, opcmethod, opcname, opcnamespace)
  	po := PgOpclass{}
  
  	err = db.QueryRow(sqlstr, opcmethod, opcname, opcnamespace).Scan(&po.Tableoid, &po.Cmax, &po.Xmax, &po.Cmin, &po.Xmin, &po.Oid, &po.Ctid, &po.Opcmethod, &po.Opcname, &po.Opcnamespace, &po.Opcowner, &po.Opcfamily, &po.Opcintype, &po.Opcdefault, &po.Opckeytype)
  	if err != nil {
  		return nil, err
  	}
  
  	return &po, nil
  }
docs: // PgOpclassByOpcmethodOpcnameOpcnamespace retrieves a row from 'pg_catalog.pg_opclass' as a PgOpclass.
  //
  // Generated from index 'pg_opclass_am_name_nsp_index'.