分離した先の表ではPK.それを参照している元の表ではFKを追加。
I wonder what is the meaning of ”先“ in “分離した先の表ではPK”. Is this refer to the original table or different table?
I also find a lot 先 in words such as 宛先 and ログ先書きプロトコル What does this means? 先 means previous but i think it dont apply here(?)
The paragraph is talking about database normalization rule. There is the original table which have some redundant columns. Your task is to divide the original table into two new tables, but in practical situations such is unlikely to be happened. instead you would need to remove some columns from the original table and then create another table with those columns.
The primary keys and foreign keys are needed to tag their relations.
Now the original table is referred as 分離元の表 and the new table is called 分離先の表.
divide from=元 divide into=先
宛先 is a word. there is no such 宛元.
ログ先書き(saki-gaki)プロトコル is an abridged version of ログ先行書き込み(senkou-kakikomi)プロトコル which is a direct translation of Write-Ahead Logging (WAL).
opposite of 先行 is 後続.(preceding -> following)
These 3 先 usages look quite diffrent each other.
先 is one of those kanji which modifies kanji preceding it or following it.
For your first question, it refers to the same table from what I understand. [Is is from a technical spec?]
My understanding - In the separated table above [PK], add FK to it.
[元の表で quite literally refers to "table of origin"]
For your second question, 宛先 refers to "address" or "destination":
この宛先におくってもらえませんか。 Could you send it to this address? [Kono atesaki ni okutte moraemasen ka?]
So in this instance, 先 is referring to "ahead" - you send things forward/ahead/to somewhere.
ログ先書きプロトコル is quite literally "Logging protocol". Here 先 obviously refers to something that happened previously - you log things which have happened.
[先書 means "log writing" in loose terms.]
This is what I meant by 先 having its meaning modified depending on the preceding of following kanji. It can mean "ahead/forward" in some circumstances, and "previous" in others as you correctly noted.
Other examples; an example of precedence in mazu, and looking ahead in sakiwamari:
先ず - mazu - First of all,...
先回り - sakimawari - going on ahead / anticipating [something]
Hope it helps.
