如果有H(key)=key mod 13，若：key1=12,key2=25，那么key1与key2是同义词。
举一反三
- 下面的SQL哪些有可能经过两个阶段（只经过一次shuffle）就计算出结果：（ ） A: SELECT key1, key2, SUM(value1) FROM (SELECT key1, key2, COUNT(*) FROM dual GROUP BY key1, key2) t1 GROUP BY key2, key1; B: SELECT a.key1, a.key2 FROM table1 a JOIN table2 b ON a.key1 = b.key; C: SELECT *, ROW_NUMBER() OVER(PARTITION BY key ORDER BY value1, value 2) id1, ROW_NUMBER() OVER(PARTITION BY key ORDER BY value1) id2 FROM dual;
- 对不同的关键字可能得到同一哈希地址，即key≠key2而H（key1）=H（key2）这种现象称冲突。（）. A: 对 B: 错
- 关键码key实际存放的位置是： A: key B: key - 1 C: hash(key) D: hash(hash(key))
- D = {'苹果': 4, '梨': 5, '榴莲': 1} D2 = {'香蕉': 3, '柠檬': 3, '凤梨':2 , '苹果':3} for key in D: for key2 in D2: if key == key2: print(D[key]+D2[key2]) 以上代码运行结果为（ ）? A: 10 B: 5 C: 7 D: 21
- Four keys to getting hired are begun in different ways stylistically. Key 1 starts with a ____.Key 2 starts with a ___. Key 3 starts with a ____. Key4 starts with a ____.