Commit 049afa3b authored by Rene Saarsoo's avatar Rene Saarsoo
Browse files

Add vote column to comments table. 

The script update_votes.sql calculates the values for that column based
on the entries in votes table.

This is an optimization to avoid aggregating the votes in a separate
table every time we retrieve comments.

Also updated examples.sql to use the new full_visible_comments view -
this greatly simplified all queries.
parent 08ab4f5f

comments/examples.sql

+34 −29
Original line number Diff line number Diff line
@@ -2,52 +2,57 @@ 


-- get comments for a particular member



SELECT * FROM visible_comments c JOIN targets ON c.target_id = targets.id

WHERE targets.domain = ? AND targets.type = ? AND targets.cls = ? AND targets.member = ?

SELECT *

FROM visible_comments

WHERE domain = ? AND type = ? AND cls = ? AND member = ?;



-- get 100 most recent comments



SELECT * FROM visible_comments c JOIN targets ON c.target_id = targets.id

WHERE targets.domain = ?

ORDER BY created_at DESC LIMIT 100

SELECT *

FROM full_visible_comments

WHERE domain = 'ext-js-4'

ORDER BY created_at DESC

LIMIT 100;



-- get number of comments for each target



SELECT

    target.type AS type,

    target.cls AS cls,

    target.member AS member,

    type AS type,

    cls AS cls,

    member AS member,

    count(*) AS cnt

FROM visible_comments c JOIN targets ON c.target_id = targets.id

WHERE target.domain = ?

GROUP BY target.id

FROM full_visible_comments

WHERE domain = 'ext-js-4'

GROUP BY target_id

ORDER BY cnt;



-- get number of comments for each class (including comments for class members)



SELECT

    target.cls AS cls,

    cls AS cls,

    count(*) AS cnt

FROM visible_comments c JOIN targets ON c.target_id = targets.id

WHERE target.domain = ? AND target.type = 'class'

GROUP BY target.cls

FROM full_visible_comments

WHERE domain = 'ext-js-4' AND type = 'class'

GROUP BY cls

ORDER BY cnt;



-- get users with most upvotes



SELECT

    users.username,

    SUM(c.vote) AS votes

FROM users LEFT JOIN voted_comments c ON c.user_id = users.id

GROUP BY users.id

    username,

    SUM(vote) AS votes

FROM full_visible_comments

GROUP BY username

ORDER BY votes DESC

LIMIT 10;



-- get users with most downvotes



SELECT

    users.username,

    SUM(c.vote) AS votes

FROM users LEFT JOIN voted_comments c ON c.user_id = users.id

GROUP BY users.id

    username,

    SUM(vote) AS votes

FROM full_visible_comments

GROUP BY username

HAVING votes IS NOT NULL

ORDER BY votes ASC

LIMIT 10;
@@ -55,10 +60,10 @@ LIMIT 10; 
-- get users with most comments



SELECT

    users.username,

    username,

    COUNT(*) AS comment_count

FROM users LEFT JOIN visible_comments c ON c.user_id = users.id

GROUP BY users.id

FROM full_visible_comments

GROUP BY username

ORDER BY comment_count DESC

LIMIT 10;
@@ -77,7 +82,7 @@ LIMIT 10; 
SELECT

    username,

    COUNT(*) AS comment_count

FROM users LEFT JOIN visible_comments c ON c.user_id = users.id

WHERE users.moderator = 1

GROUP BY users.id

FROM full_visible_comments

WHERE moderator = 1

GROUP BY username

ORDER BY comment_count DESC;

comments/schema.sql

+4 −13
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ CREATE TABLE comments ( 
    target_id INT NOT NULL,

    content TEXT NOT NULL,

    content_html TEXT NOT NULL,

    vote INT NOT NULL DEFAULT 0,

    created_at DATETIME NOT NULL,

    deleted BOOLEAN NOT NULL DEFAULT 0,

    FOREIGN KEY (user_id) REFERENCES users (id) ON DELETE CASCADE,
@@ -72,20 +73,11 @@ CREATE TABLE readings ( 
    CONSTRAINT unique_readings UNIQUE KEY (user_id, comment_id)

) ENGINE = InnoDB, CHARACTER SET = utf8;



CREATE VIEW visible_comments AS SELECT * FROM comments WHERE deleted = 0;



CREATE VIEW voted_comments AS SELECT

    c.*,

    SUM(v.value) AS vote

FROM visible_comments c LEFT JOIN votes v ON c.id = v.comment_id

GROUP BY c.id;

CREATE OR REPLACE VIEW visible_comments AS SELECT * FROM comments WHERE deleted = 0;



-- comments table joined with users and targets for easier quering

CREATE VIEW full_visible_comments AS SELECT

    c.id,

    c.content,

    c.content_html,

    c.created_at,

CREATE OR REPLACE VIEW full_visible_comments AS SELECT

    c.*,

    users.username,

    users.external_id,

    users.email,
@@ -97,4 +89,3 @@ CREATE VIEW full_visible_comments AS SELECT 
FROM visible_comments AS c

    LEFT JOIN users ON c.user_id = users.id

    LEFT JOIN targets ON c.target_id = targets.id;

comments/update_votes.sql

0 → 100644
+4 −0
Original line number Diff line number Diff line 
-- calculates the votes column for all comments



UPDATE comments

SET vote = (SELECT SUM(value) FROM votes WHERE votes.comment_id = comments.id);