如何从视图的连接和后续查询中索引视图？

Question

我是 sql 索引的新手，想要索引它

CREATE TABLE IF NOT EXISTS message (
    id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
    remoteId TEXT,
    text TEXT,
    timestamp INTEGER NOT NULL DEFAULT 0,
    channelId TEXT NOT NULL,
    accountId TEXT NOT NULL,

    username TEXT NOT NULL,
    editUsername TEXT,
    wm_createdUsername TEXT,
    wm_organizedUsername TEXT,
    rc_username TEXT,
    p_messageRemoteId TEXT,
    c_messageRemoteId TEXT,
    ....

    UNIQUE (remoteId, accountId),
    FOREIGN KEY (channelId, accountId) REFERENCES channel(id, accountId) ON DELETE CASCADE,
    FOREIGN KEY (p_messageRemoteId, accountId) REFERENCES message(remoteId, accountId) ON DELETE CASCADE,
    FOREIGN KEY (c_messageRemoteId, accountId) REFERENCES message(remoteId, accountId) ON DELETE CASCADE
);

CREATE VIEW messageAndUser AS
SELECT ...
FROM message
LEFT JOIN user AS u ON message.username = u.name AND message.accountId = u.accountId
LEFT JOIN user AS e ON message.editUsername = e.name AND message.accountId = e.accountId
LEFT JOIN user AS wm ON message.wm_organizedUsername = wm.name AND message.accountId = wm.accountId
LEFT JOIN user AS rc ON message.rc_username = rc.name AND message.accountId = rc.accountId
LEFT JOIN user AS i ON message.i_username = i.name AND message.accountId = i.accountId;

频道消息：

SELECT *
FROM messageAndUser
WHERE channelId=? AND accountId=?
ORDER BY timestamp DESC

;

我的直觉告诉我，索引需要放在AND语句的所有部分作为一个单元。

但是我不知道该怎么做是，如果我有一个涵盖视图中连接的所有部分的索引，现在如果来自该视图的查询，即select from view where foo=?，我是否需要创建新的索引包含视图 + foo 的索引中的所有列？或者有没有办法组成这个？

Answer 1

视图不能直接被索引，但可以从视图查询中涉及的表上的索引中受益。

查看您的架构和视图似乎您错过了连接的主索引

table  message  column   accountId

做到唯一索引UNIQUE（remoteId，accountId在右侧显示accountId..这对于视图中使用的连接没有用处..