A. You can join a maximum of two tables through an equijoin.
B. You can join a maximum of two columns through an equijoin.
C. You specify an equijoin condition in the SELECT or FROM clauses of a SELECT statement.
D. To join two tables through an equijoin, the columns in the join condition must be primary key and foreign key columns.
E. You can join n tables (all having single column primary keys) in a SQL statement by specifying a minimum of n-1 join conditions.
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A. string
B. character
C. integer
D. calendar
E. numeric
F. translation
G. date
H. conversion
A. MAX
B. MIN
C. SUM
D. COUNT
E. TOTAL
F. LARGEST
A. The main query executes with the first value returned by the subquery.
B. The main query executes with the last value returned by the subquery.
C. The main query executes with all the values returned by the subquery.
D. The main query fails because the multiple-row subquery cannot be used with the comparison operator.
E. You cannot define a multiple-row subquery in the WHERE clause of a SQL query.
A SELECT statement can be used to perform these three functions:
1. Choose rows from a table.
2. Choose columns from a table
3. Bring together data that is stored in different tables by creating a link between them.
Which set of keywords describes these capabilities?（）
A. difference, projection, join
B. selection, projection, join
C. selection, intersection, join
D. intersection, projection, join
E. difference, projection, product
A. Constraints provide data independence.
B. Constraints make complex queries easy.
C. Constraints enforce rules at the view level.
D. Constraints enforce rules at the table level.
E. Constraints prevent the deletion of a table if there are dependencies.
F. Constraints prevent the deletion of an index if there are dependencies.
A. CREATE TABLE EMP9$# AS (empid number(2));
B. CREATE TABLE EMP*123 AS (empid number(2));
C. CREATE TABLE PACKAGE AS (packid number(2));
D. CREATE TABLE 1EMP_TEST AS (empid number(2));
A. TRIM
B. REPLACE
C. TRUNC
D. TO_DATE
E. MOD
F. CASE
A. A MERGE statement is used to merge the data of one table with data from another.
B. A MERGE statement replaces the data of one table with that of another.
C. A MERGE statement can be used to insert new rows into a table.
D. A MERGE statement can be used to update existing rows in a table.
Evaluate this SQL statement:
In the statement, which capabilities of a SELECT statement are performed?（）
A. Selection, projection, join
B. Difference, projection, join
C. Selection, intersection, join
D. Intersection, projection, join
E. Difference, projection, product
A. The UNIQUE constraint does not permit a null value for the column.
B. A UNIQUE index gets created for columns with PRIMARY KEY and UNIQUE constraints.
C. The PRIMARY KEY and FOREIGN KEY constraints create a UNIQUE index.
D. The NOT NULL constraint ensures that null values are not permitted for the column.
最新试题
Evaluate this SQL statement:SELECT e.emp_name, d.dept_nameFROM employees eJOIN departments dUSING (department_id)WHERE d.department_id NOT IN (10,40)ORSER BY dept_name;The statement fails when executed. Which change fixes the error? （）
Examine these statements:CREATE ROLE registrarGRANT UPDATE ON dtudent_grades TO registrar;GRANT registrar to user1, user2, user3;What does this set of SQL statements do? （）
Which is an iSQL*Plus command? （）
Examine the structure of the EMPLOYEES table:EMPLOYEE_ID NUMBER NOT NULL, Primary KeyEMP_NAME VARCHAR2(30)JOB_ID NUMBER\SAL NUMBERMGR_ID NUMBER References EMPLOYEE_ID columnDEPARTMENT_ID NUMBER Foreign key to DEPARTMENT_ID column of the DEPARTMENTS table You created a sequence called EMP_ID_SEQ inorderto populate sequential values for the EMPLOYEE_ID column of the EMPLOYEES table. Which two statements regarding the EMP_ID_SEQ sequence are true? （）
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Evaluate these two SQL statements: SELECT last_name, salary, hire_dateFROM EMPLOYEES ORDRE BY salary DESC; SELECT last_name, salary, hire_dateFROM EMPOLYEES ORDER BY 2 DESC; What is true about them? （）
Which two statements about subqueries are true? （）
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Which view should a user query to display the columns associated with the constraints on a table owned by the user? （）
Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary KeyFIRST_NAME VARCHAR2 (25)LAST_NAME VARCHAR2 (25)HIRE_DATE DATEWhich UPDATE statement is valid? （）