MongoDB Answers S3

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Answers to Section 3

Exercise 3.1

• Compare how you added the above data and how it differs from INSERT records in a relational database

Think about how this differs from using INSERT statements in Oracle to add the data. An SQL INSERT generally only insert one record at a time to one table.

• * Add Department 30 and its employees as a nested array.

The department document has the following key/values: deptno: 30, dname: SALES and loc: CHICAGO

The employee details are as follows:

EMPNO	ENAME	JOB	MGR	HIREDATE	SAL	COMM	DEPTNO
7499	ALLEN	SALESMAN	7698	20-FEB-95	1600	300	30
7698	BLAKE	MANAGER	7839	01-MAY-81	2850		30
7900	JAMES	CLERK	7698	03-DEC-81	950		30
7654	MARTIN	SALESMAN	7698	28-SEP-93	1250	1400	30
7844	TURNER	SALESMAN	7698	08-SEP-81	1500	0	30
7521	WARD	SALESMAN	7698	22-FEB-94	1250	500	30

db.deptCollection.insert( 
 {
    deptno: 30, 
    dname: 'SALES',
    loc: 'CHICAGO',
    employees: [
    {
        empno: 7499,
        ename: 'ALLEN',	
        job: 'SALESMAN',
        mgr: 7698, 	
        hiredate: new Date('1995-02-20'),
        sal: 1600,
        comm: 300
    },
    {
        empno: 7698,
        ename: 'BLAKE',	
        job: 'MANAGER',
        mgr: 7839, 	
        hiredate: new Date('1981-05-01'),
        sal: 2850
    }, 	 	 	 	
    {   empno: 7900,
        ename: 'JAMES',	
        job: 'CLERK',
        mgr: 7698, 	
        hiredate: new Date('1981-12-03'),
        sal: 1600
    },
    {
        empno: 7654,
        ename: 'MARTIN',	
        job: 'SALESMAN',
        mgr: 7698, 	
        hiredate: new Date('1993-09-28'),
        sal: 1250,
        comm: 1400
    },
    {   empno: 7844,
        ename: 'TURNER',	
        job: 'SALESMAN',
        mgr: 7698, 	
        hiredate: new Date('1981-09-08'),
        sal: 1500,
        comm: 0
    },
    {
        empno: 7521,
        ename: 'WARD',	
        job: 'SALESMAN',
        mgr: 7698, 	
        hiredate: new Date('1994-02-22'),
        sal: 1250,
        comm: 500
    } ]
 })

Exercise 3.2

2.2.1 Update the name of department 40 to: COMPUTING

 db.deptCollection.update({deptno:40}, 
  {$set:  {dname: 'COMPUTING'}})

2.2.1 Update the salary of employee number 7788 in department 20 to 3500

db.deptCollection.update (
{ deptno: 20 , "employees.empno": 7788}, 
  { $set: {"employees.$.sal" : 3500} }  
)

Always check that your update has worked. As a clue, the system should output a WriteResult, telling you how many records were updated:

WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

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