差压阀装用在CW-200K型转向架上时，两空气弹簧的允许压差为（）。 （110±10）kPa。 （120±10）kPa。 （20±10）kPa。 （150±20）kPa。
You are a professional level SQL Server 2005 database administrator in an international corporation named Wiikigo. You are experienced in implementing high-availability solutions， monitoring the database server， and design deployment. In the company， you major job is the deployment， maintenance and support of Microsoft SQL Server 2005.You work as a database administrator for your company. A SQL Server 2005 database is utilized in your company. And a table named Inventory is contained by the database. A column named Price is included by the table. According to the company policy， you cannot reduce more than 10 percent the value in the Price column in any single database operation. Through many kinds of method， the company makes updates to the Price column. For instance， the utilization of ad hoc queries is one of the methods. Since you are the database administrator， you should confirm that this company policy takes its effect. Which action should be performed？（） A stored procedure should be created， and changes are disallowed by the procedure to the Price column that violates company policy.。 On the Price column， a check constraint should be created， and a specified minimum value is required by the check constraint.。 A trigger should be created， and changes are rolled back by the trigger to the Price column that violates company policy.。 On the Price column， a foreign key constraint is created to a table that valid prices are included.。
如果课堂充满了（），没有提炼和提升，就没有进步。
两只阻值相同的电阻串联后，其阻值（）。 等于两只阻值的乘积。 等于两只阻值的和。 等于两只阻值的二分之一。
You need to design a student registration database that contains several tables storing academic information. The STUDENTS table stores information about a student. The STUDENT_GRADES table stores information about the student's grades. Both of the tables have a column named STUDENT_ID. The STUDENT_ID column in the STUDENTS table is a primary key. You need to create a foreign key on the STUDENT_ID column of the STUDENT_GRADES table that points to the STUDENT_ID column of the STUDENTS table. Which statement creates the foreign key?（） CREATE TABLE student_grades (student_id NUMBER(12),semester_end DATE, gpa NUMBER(4,3), CONSTRAINT student_id_fk REFERENCES (student_id) FOREIGN KEY student (student_id));。 CREATE TABLE student_grades(student_id NUMBER(12),semester_end DATE, gpa NUMBER(4,3), student_id_fk FOREIGN KEY (student_id) REFERENCES students (student_id));。 CREATE TABLE student_grades(student_id NUMBER(12),semester_end DATE, gpa NUMBER(4,3), CONSTRAINT FOREIGN KEY (student_id) REFERENCES student (student_id));。 CREATE TABLE student_grades(student_id NUMBER(12),semester_end DATE, gpa NUMBER(4,3), CONSTRAINT student_id_fk FOREIGN KEY (student_id) REFERENCES students (student_id))。
In your running instance， some of the initialization parameters are set as shown below： SGA_MAX_SIZE = 14GB
DB_CACHE_SIZE = 1GB
SHARED_POOL_SIZE = 3GB
STATISTICS_LEVEL = BASIC
PGA_AGGREGATE_TARGET = 0
You plan to enable Automatic Shared Memory Management but you are not able to set SGA_TARGET to a nonzero value. What could be the reason？（）
