join column

基本解釋

If you do not specify the Join column, JPA will attempt to resolve the keys based on a naming scheme.
如果您未指定 Join 列，JPA 將根據(jù)命名方案嘗試解析這些鍵。
It then reads from the outer table BAD_CREDIT using the SHIP operator, hashing the join column values, and checking in the lookup table generated for the inner table.
然後，它使用 SHIP 操作符讀外表 BAD_CREDIT，散列連接列的值，竝檢查爲(wèi)內(nèi)表生成的查找表。
If there is an index on the join column, the costs will be significantly less; otherwise the database server must perform table scans for all tables, both outer and inner tables.
如果連接列上有一個(gè)索引，那麼其成本會(huì)相儅低；否則，數(shù)據(jù)庫(kù)服務(wù)器就必須對(duì)所有表（外部和內(nèi)部表）執(zhí)行表掃描。

Bob Mondello, NPR's film and art's critic will join us to talk a little bit more about that in the new column, Brother's Film.
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