带大写字母的cassandra键空间

Question

使用框架Cassandra Achilles，它生成下面的CQL，但仅当键空间名称为小写时才有效

Session session = cluster.connect();
session.execute("DROP KEYSPACE IF EXISTS Smart;");
session.execute("CREATE KEYSPACE Smart WITH replication = { "                  
                  + " 'class': 'SimpleStrategy',  'replication_factor': '3' }; ");
session.execute("CREATE TYPE IF NOT EXISTS smart.bio_udt("+
                "birthplace text,"+
                "diplomas list<text>,"+
                "description text);");
session.execute("CREATE TABLE IF NOT EXISTS Smart.users("+
                "id bigint,"+
                "age_in_year int,"+
                "bio frozen<\"Smart\".bio_udt>,"+
                "favoritetags set<text>,"+
                "firstname text,"+
                "lastname text,"+
                "preferences map<int, text>,"+
                "PRIMARY KEY(id))");

错误：

com.datastax.driver.core.exceptions.InvalidQueryException: 
Statement on keyspace smart cannot refer to a user type in keyspace Smart; 
user types can only be used in the keyspace they are defined in

有什么问题？

Answer 1

问题是对失败的 UDT 创建查询的检查区分大小写，而所有其他查询则不区分大小写。因为您没有提供 "Smart" 语法，Cassandra 认为您的意思是 "smart" 全部小写。

因此，如果您编写要运行的最终查询，您所要做的就是像这样编写：

CREATE TABLE IF NOT EXISTS Smart.users(
  id bigint,
  age_in_year int,
  bio frozen<"smart".bio_udt>,
  favoritetags set<text>,
  firstname text,lastname text,
  preferences map<int, text>,
  PRIMARY KEY(id)
);

你其实有好几种选择，可以用smart、Smart、"smart"，但不能用"Smart"，因为前三个指的是同一个东西，即 smart，但最后一个变体告诉 Cassandra “我正在寻找具有这种精确大小写的键空间，以大写 S.

开头

如果没有引号符号，Cassandra 认为您指的是不区分大小写的键空间，这将默认将其全部小写。

作为证据，在 cqlsh 中试试这个：

cqlsh> CREATE KEYSPACE THISISUPPER WITH replication = { 'class': 'SimpleStrategy',  'replication_factor': '3' };
cqlsh> DESCRIBE KEYSPACE thisisupper ;

CREATE KEYSPACE thisisupper WITH replication = {'class': 'SimpleStrategy', 'replication_factor': '3'}  AND durable_writes = true;

如果您真的想让它全部区分大小写，请使用引号，然后您将无法访问它，除非您输入键空间的确切名称。

cqlsh> CREATE KEYSPACE "HEYAQUOTES" WITH replication = { 'class': 'SimpleStrategy',  'replication_factor': '3' };
cqlsh> DESCRIBE KEYSPACE heyquotes;

Keyspace 'heyquotes' not found.
cqlsh> DESCRIBE KEYSPACE "heyaquotes";

Keyspace 'heyaquotes' not found.
cqlsh> DESCRIBE KEYSPACE HEYAQUOTES;

Keyspace 'heyaquotes' not found.
cqlsh> DESCRIBE KEYSPACE "HEYAQUOTES";

CREATE KEYSPACE "HEYAQUOTES" WITH replication = {'class': 'SimpleStrategy', 'replication_factor': '3'}  AND durable_writes = true;

带大写字母的cassandra键空间

cassandra keyspace with capital letter

cassandra

datastax