单项选择题
A. Once created, a sequence belongs to a specific schema.
B. Once created, a sequence is linked to a specific table.
C. Once created, a sequence is automatically available to all users.
D. Only the DBA can control which sequence is used by a certain table.
E. Once created, a sequence is automatically used in all INSERT and UPDATE statements.
单项选择题 In which scenario would index be most useful?（）
单项选择题 The EMPLOYEES table contains these columns: EMPLOYEE_ID NUMBER(4) LAST_NAME VARCHAR2 (25) JOB_ID VARCHAR2(10) You want to search for strings that contain SA_ in the JOB_ID column. Which SQL statement do you use?（）
单项选择题 Examine the structure of the EMPLOYEES table: You issue these statements: At the end of this transaction, what is true?（）