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<p>如果<code>does not</code>存在于数据库中,如何将这些<code>artist</code>插入数据库。我写了以下代码。但这是错误的。你能帮帮我吗?谢谢</p>
<p>艺术家列表</p>
<pre><code>Lata Mangeshkar
Lata Mangeshkar
Lata Mangeshkar
Asha Bhosle
Lata Mangeshkar
Mahendra Kapoor
Lata Mangeshkar
Kishore Kumar
Lata Mangeshkar
</code></pre>
<p>我的代码</p>
^{pr2}$
<p>输出:</p>
<pre><code>INSERT INTO song_artist (name,slug) VALUES (Lata Mangeshkar,lata-mangeshkar) RET
URNING id;
INSERT INTO song_artist (name,slug) VALUES (Lata Mangeshkar,lata-mangeshkar) RET
URNING id;
INSERT INTO song_artist (name,slug) VALUES (Lata Mangeshkar,lata-mangeshkar) RET
URNING id;
INSERT INTO song_artist (name,slug) VALUES (Lata Mangeshkar,lata-mangeshkar) RET
URNING id;
INSERT INTO song_artist (name,slug) VALUES (Asha Bhosle,asha-bhosle) RETURNING i
d;
INSERT INTO song_artist (name,slug) VALUES (Lata Mangeshkar,lata-mangeshkar) RET
URNING id;
INSERT INTO song_artist (name,slug) VALUES (Mahendra Kapoor,mahendra-kapoor) RET
URNING id;
INSERT INTO song_artist (name,slug) VALUES (Mahendra Kapoor,mahendra-kapoor) RET
URNING id;
INSERT INTO song_artist (name,slug) VALUES (Lata Mangeshkar,lata-mangeshkar) RET
URNING id;
</code></pre>
<p>输出应为:</p>
<pre><code>INSERT INTO song_artist (name,slug) VALUES (Asha Bhosle,asha-bhosle) RETURNING i
d;
INSERT INTO song_artist (name,slug) VALUES (Lata Mangeshkar,lata-mangeshkar) RET
URNING id;
INSERT INTO song_artist (name,slug) VALUES (Mahendra Kapoor,mahendra-kapoor) RET
URNING id;
</code></pre>
<p>更新:</p>
<p>我已经在列名上添加了约束,以强制列是唯一的。在</p>