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Answers to Section 2

Exercise 2.1

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

A SQL INSERT statement for department 30 would be:

INSERT INTO dept(deptno, dname, loc) VALUES (30,'SALES','CHICAGO');

Apart from the syntax differences, you could get away with not defining the field names again, for example, this would work too:

INSERT INTO dept VALUES (30,'SALES','CHICAGO');

This is because the table has already been defined, so there is a well defined schema in existence. MongoDB is schemaless, so you need to define some sort of structure as the documents are added.

• Try and add Department 30

db.dept.insert(
 {
	_id: 30,
    deptno: 30,
    dname:  "SALES",
    loc:    "CHICAGO"
})

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.

• Try and add Department 30. Note it has some values for the comm field.

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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