英文:
How to set foreign key with compound primary key in Kdb+?
问题
这里是您要翻译的部分：
"有关如何设置外键的文件已足够，但关于如何设置具有复合主键/外键的文件很少。
我运行以下命令，并报告最后2个“length”。如何正确设置它？
t:([eid:1001 1002 1003] name:DentBeeblebroxPrefect; iq:98 42 126) kt: eid`name xkey kt
td2:([] eid:kt$1003 1001 1002 1001 1002 1001; sc:126 36 92 39 98 42) // lenght
td3:([] eid:kt$1003 1001 1002 1001; name:kt$PrefectDentBeeblebroxDent sc:126 36 92 39) // `length"
英文:
It is sufficient documents about how to set foreign key, but few about how to set with compound primary/foreign key.
I run following commands and the last 2 reported `length. How to set it correctly?
t:([eid:1001 1002 1003] name:`Dent`Beeblebrox`Prefect; iq:98 42 126)kt: `eid`name xkey kttd2:([] eid:`kt$1003 1001 1002 1001 1002 1001; sc:126 36 92 39 98 42) // `lenghttd3:([] eid:`kt$1003 1001 1002 1001; name:`kt$`Prefect`Dent`Beeblebrox`Dent sc:126 36 92 39) // `length
答案1
得分: 1
Compound keys can be achieved as outlined in:
q)kt:([eid:1001 1002 1003;name:`Dent`Beeblebrox`Prefect] iq:98 42 126)q)kteid name | iq---------------| ---1001 Dent | 981002 Beeblebrox| 421003 Prefect | 126q)td:([] eid:1003 1001 1002 1001; name:`Prefect`Dent`Beeblebrox`Dent; sc:126 36 92 39)q)tdeid name sc-------------------1003 Prefect 1261001 Dent 361002 Beeblebrox 921001 Dent 39q)update ktfkey:`kt$(eid,'name) from `td // ,' creates (eid;name) pairs`tdq)tdeid name sc ktfkey--------------------------1003 Prefect 126 21001 Dent 36 01002 Beeblebrox 92 11001 Dent 39 0q)select eid,name,sc,ktfkey.iq from tdeid name sc iq-----------------------1003 Prefect 126 1261001 Dent 36 981002 Beeblebrox 92 421001 Dent 39 98
英文:
Compount keys can be achieved as outlined in:
q)kt:([eid:1001 1002 1003;name:`Dent`Beeblebrox`Prefect] iq:98 42 126)q)kteid name | iq---------------| ---1001 Dent | 981002 Beeblebrox| 421003 Prefect | 126q)td:([] eid:1003 1001 1002 1001; name:`Prefect`Dent`Beeblebrox`Dent; sc:126 36 92 39)q)tdeid name sc-------------------1003 Prefect 1261001 Dent 361002 Beeblebrox 921001 Dent 39q)update ktfkey:`kt$(eid,'name) from `td // ,' creates (eid;name) pairs`tdq)tdeid name sc ktfkey--------------------------1003 Prefect 126 21001 Dent 36 01002 Beeblebrox 92 11001 Dent 39 0q)select eid,name,sc,ktfkey.iq from tdeid name sc iq-----------------------1003 Prefect 126 1261001 Dent 36 981002 Beeblebrox 92 421001 Dent 39 98
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