Question

所以我附加了多个数据库，然后创建了一个TEMP VIEW，它结合了各种数据库中的所有虚拟表。

theDatabase.execSQL("CREATE TEMP VIEW virtualView AS SELECT * FROM Virtual_Sites UNION SELECT * FROM db1.Virtual_Sites UNION SELECT * FROM db2.Virtual_Sites");

是否可以在此VIEW上使用MATCH查询？

theDatabase.rawQuery(SELECT * FROM virtualView WHERE all_text MATCH 21033, null)

我目前收到此错误。

sqlite returned: error code = 1, msg = statement aborts at 46: [SELECT * FROM virtualView WHERE all_text MATCH 21033] unable to use function MATCH in the requested context, db=xxx

exception: SQL logic error or missing database; query: SELECT * FROM virtualView WHERE all_text MATCH 21033

我已经读过以这种方式创建VIEW不会继承基础表索引，这就是我无法做MATCH的原因吗？如果有任何解决方法？

由于

Answer 1

MATCH仅适用于实现此运算符的虚拟表，而不适用于视图。

您必须重写所有查询才能在各个表格上使用MATCH，并将这些结果与UNION ALL合并。

或者，将所有表的数据复制到一个临时表中。

Answer 2

这是我发现的。 VIEWS在组合多个数据库/表时效率不高，因为它们在包含2个以上表时会松散其下划线索引。

<强> ATTACH

String newDbPath = DB_PATH + DB_NAME;
theDatabase.execSQL("ATTACH DATABASE '" + newDbPath + "' as db1;");

效率低下

Create VIEW
theDatabase.execSQL("CREATE TEMP VIEW view1 AS SELECT * FROM Sites_hsf UNION SELECT * FROM db1.Sites_hsf UNION SELECT * FROM db2.Sites_hsf;");

Query VIEW
sqlStatement = "SELECT * FROM view1 s INNER JOIN view2 con ON s.site_uid = con.site_uid AND con.ap_active = 1 WHERE s.site_uid = 1114331";

执行时间 16281毫秒

有效的方式

sqlStatement = "SELECT * FROM Sites_hsf s INNER JOIN Connections_hsf con ON s.site_uid = con.site_uid AND con.ap_active = 1 WHERE s.site_uid = 1114331 " +
                "UNION ALL " +
                "SELECT * FROM db1.Sites_hsf s1 INNER JOIN db1.Connections_hsf con1 ON s1.site_uid = con1.site_uid AND con1.ap_active = 1 WHERE s1.site_uid = 1114331 " +
                "UNION ALL " +
                "SELECT * FROM db2.Sites_hsf s2 INNER JOIN db2.Connections_hsf con2 ON s2.site_uid = con2.site_uid AND con2.ap_active = 1 WHERE s2.site_uid = 1114331";

执行时间 4毫秒

使用CL。对UNION ALL的答案进行匹配

sqlStatement = "SELECT * FROM Virtual_Sites_hsf WHERE all_text MATCH '40227' " +
                "UNION ALL SELECT * FROM db1.Virtual_Sites_hsf WHERE all_text  MATCH '40227'" +
                "UNION ALL SELECT * FROM db2.Virtual_Sites_hsf WHERE all_text  MATCH '40227'"

希望这有助于某人。

SQLite3在视图上匹配？

2 个答案: