不兼容的SQL触发器

作为SQL的新手，有人能帮我将这个触发器调整为sqlite或HSQLDB，或者建议一种不同的方法吗

我的数据库中有此表：

CREATE TABLE IF NOT EXISTS dfTree 
(
id INTEGER, 
parentId INTEGER,
name VARCHAR(20),
depth INTEGER,
lineage VARCHAR(100)
)

我尝试设置触发器，但它似乎与我尝试的sqlite和HSQLDB都不兼容

CREATE TRIGGER dfTree_InsertTrigger ON dfTree
FOR INSERT AS
UPDATE child
    -- set the depth of this "child" to be the
    -- depth of the parent, plus one.
    SET depth = ISNULL(parent.depth + 1,0),
    -- the lineage is simply the lineage of the parent,
    -- plus the child's ID (and appropriate '/' characters
    lineage = ISNULL(parent.lineage,'/') + LTrim(Str(child.id)) + '/'
-- we can't update the "inserted" table directly,
-- so we find the corresponding child in the
-- "real" table
FROM dfTree child INNER JOIN inserted i ON i.id=child.id
-- now, we attempt to find the parent of this
-- "child" - but it might not exist, so these
-- values may well be NULL
LEFT OUTER JOIN dfTree parent ON child.parentId=parent.id

触发器应该在新条目时计算深度和沿袭字段。我正在看《树木结构》的文章

再说一次，作为SQL的新手，有人能帮我将这个触发器调整为sqlite或HSQLDB，或者建议一种不同的方法吗

谢谢

这应该有效：

CREATE TRIGGER dfTree_InsertTrigger 
after insert ON dfTree 
for each row
begin
  UPDATE dftree SET   
    depth = (select coalesce(depth + 1, 1) from (select depth from dftree parent where parent.id = new.parentid union all select null depth)),
    lineage = (select coalesce(lineage,'/') || dftree.id || '/' from (select lineage from dftree parent where parent.id = new.parentid union all select null lineage))
  where new.id = id;
end;

几句话： -SQL中字符串连接的运算符是| |，而不是+ -coalesce应该比isnull更易于移植

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-工会全体。。part确保了即使没有家长，我们也能始终得到一条线

像个魔咒一样工作！非常感谢！