使用Chapel CDO从Postgres检索阵列

Question

我正在使用Chapel CDO库从Postgres拉一个数组的错误，我有一个PG实例，下表

DROP TABLE IF EXISTS aagg;
CREATE TABLE aagg (team text, name text);
INSERT INTO aagg VALUES ('Wonder Pets', 'Linny'); 
INSERT INTO aagg VALUES ('Wonder Pets', 'Ming Ming');
INSERT INTO aagg VALUES ('Wonder Pets', 'Tuck');
INSERT INTO aagg VALUES ('OJ Defense Team', 'F. Lee Bailey'); 
INSERT INTO aagg VALUES ('OJ Defense Team', 'Robert Shapiro');
INSERT INTO aagg VALUES ('OJ Defense Team', 'Johnny Cohchran');

我正在尝试使用以下教堂程序来拉动它

use Postgres;
config const DB_HOST: string = "localhost";
config const DB_USER: string = "buddha";
config const DB_NAME: string = "buddha";
config const DB_PWD: string = "buddha";

var con = PgConnectionFactory(host=DB_HOST, user=DB_USER, database=DB_NAME, passwd=DB_PWD);
var cursor = con.cursor();
// Retrieve the data
const q = "SELECT team, array_agg(name) AS members FROM aagg GROUP BY team;"; 
cursor.query(q);
for row in cursor {
  writeln("Team: ", row['name'], "tMembers: ", row['members'] );
  for member in row['members'] {
    writeln ("Special mention to ", member);
  }
}

但是，循环像

中分解了字符

Special mention to {
Special mention to "
Special mention to F
Special mention to .
Special mention to  
Special mention to L
Special mention to e
Special mention to e
Special mention to  
Special mention to B
Special mention to a
Special mention to i
Special mention to l
Special mention to e
Special mention to y
Special mention to "

我该如何识别该数组？谢谢！

Answer 1

使用row["column_name"]或row.get("column_name")时，将列值作为字符串获取。但是，Postgres可以使用列数组响应查询。为了治疗这一点，您应该使用方法 row.getArray("column_name") 将Postgres数组作为教堂字符串数组。

ex。：

use Postgres;
config const DB_HOST: string = "localhost";
config const DB_USER: string = "buddha";
config const DB_NAME: string = "buddha";
config const DB_PWD:  string = "buddha";
var con = PgConnectionFactory( host=DB_HOST,
                               user=DB_USER,
                               database=DB_NAME,
                               passwd=DB_PWD
                               );
var cursor = con.cursor();
// Retrieve the data
const q = "SELECT team, array_agg(name) AS members FROM aagg GROUP BY team;"; 
cursor.query(q);
for row in cursor {
  writeln("Team: ", row['name'], "tMembers: ", row['members'] );
  for member in row.getArray("members") {
    writeln ("Special mention to ", member);
  }
}