单项选择题
Which constraint can be defined only at the column level? （）
A. UNIQUE
B. NOT NULL
C. CHECK
D. PRIMARY KEY
E. FOREIGN KEY
相关考题
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多项选择题
In which two cases would you use an outer join? （）
A. The tables being joined have NOT NULL columns.
B. The tables being joined have only matched data.
C. The columns being joined have NULL values.
D. The tables being joined have only unmatched data.
E. The tables being joined have both matched and unmatched data.
F. Only when the tables have a primary key/foreign key relationship. -
单项选择题
The PRODUCTS table has these columns: PRODUCT_ID NUMBER(4) PRODUCT_NAME VARCHAR2(45) PRICE NUMBER(8,2) Evaluate this SQL statement: SELECT * FROM PRODUCTS ORDER BY price, product _ name; What is true about the SQL statement? （）
A. The results are not sorted.
B. The results are sorted numerically.
C. The results are sorted alphabetically.
D. The results are sorted numerically and then alphabetically. -
单项选择题
Which best describes an inline view? （）
A. a schema object
B. a subquery that can contain an ORDER BY clause
C. another name for a view that contains group functions
D. a subquery that is part of the FROM clause of another query
