如何在 CQL 3 准备好的语句中绑定 IN 子句值? [英] How to bind IN-clause values in a CQL 3 prepared statement?
问题描述
我有一张大致像的桌子
create table mytable (
id uuid,
something text,
primary key (id)
);
我正在尝试创建一个带有绑定子句的准备好的语句:
I'm trying to create a prepared statement that has a bound in-clause:
PreparedStatement ps = session.prepare("select * from mytable where id IN (?)");
...
UUID[] ids = { uuid1, uuid2, uuid3} ;
无论我如何表达要绑定的 id,java 驱动程序都会拒绝它们.
No matter how I express the ids to bind, the java driver rejects them.
ps.bind(/*as array*/)
:驱动程序抱怨语句只有一个值,提供了 2 个
ps.bind( /*as array*/)
: driver complains statement has only one value, 2 supplied
ps.bind(/*as 逗号分隔的 uuids 字符串列表*/)
:驱动程序抱怨它想要 UUID.class 对象,而不是字符串
ps.bind( /*as comma separated string list of uuids*/)
: driver complains it wants UUID.class objects, not strings
ps.bind(/*as list object*/)
:驱动程序抱怨它想要 UUID.class 对象,而不是 List.class 对象
ps.bind( /*as list object*/)
: driver complains it wants UUID.class objs, not a List.class object
我真的希望司机不要期待那么多?占位符,因为 in-list 中有值,因为这意味着每次要执行该语句时都必须重新准备该语句,Datastax 文档说不要这样做!
I really hope the driver isn't expecting as many ? place holders as there are values in the in-list, because that means you'd have to reprepare the statement every time you wanted to execute it, which the Datastax docs says not to do!
我查看了 com.datastax.driver.core.BoundStatement.bind()
方法,没有迹象表明其他任何方法都可以工作 - 没有魔法包装器或任何东西.
I looked at the com.datastax.driver.core.BoundStatement.bind()
method and there is no indication that anything else would work - no magic wrappers or anything.
有没有办法做到这一点?
Is there a way to do this?
推荐答案
正确的语法是 SELECT * FROM mytable WHERE id IN ?
(?
周围没有括号).这将允许您传递 UUID 列表以绑定到该单个查询参数.
The correct syntax is SELECT * FROM mytable WHERE id IN ?
(without parens around the ?
). This will allow you to pass a list of UUIDs to bind to that single query parameter.
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