Question

在SQLite 3中

如果我更新具有全文索引的字段，是否会更新全文索引，还是需要手动更新？

Answer 1

这取决于例如。如果您使用“外部内容FTS4表”，它将不会自动更新。

来自http://www.sqlite.org/fts3.html#section_6_2_2

CREATE TABLE t2(id INTEGER PRIMARY KEY, a, b, c, d);
CREATE VIRTUAL TABLE t3 USING fts4(content="t2", b, c);

INSERT INTO t2 VALUES(2, 'a b', 'c d', 'e f');
INSERT INTO t2 VALUES(3, 'g h', 'i j', 'k l');
INSERT INTO t3(docid, b, c) SELECT id, b, c FROM t2;
-- The following query returns a single row with two columns containing
-- the text values "i j" and "k l".
--
-- The query uses the full-text index to discover that the MATCH 
-- term matches the row with docid=3. It then retrieves the values
-- of columns b and c from the row with rowid=3 in the content table
-- to return.
--
SELECT * FROM t3 WHERE t3 MATCH 'k';

-- Following the UPDATE, the query still returns a single row, this
-- time containing the text values "xxx" and "yyy". This is because the
-- full-text index still indicates that the row with docid=3 matches
-- the FTS4 query 'k', even though the documents stored in the content
-- table have been modified.
--
UPDATE t2 SET b = 'xxx', c = 'yyy' WHERE rowid = 3;
SELECT * FROM t3 WHERE t3 MATCH 'k';

但也可以通过触发器来解决。

而不是单独写入全文索引和内容表中，一些用户可能希望使用数据库触发器来保持关于存储的文档集的最新全文索引在内容表中。例如，使用之前的表示例：

SQLite：编辑一个字段，全文更新？

1 个答案: