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| | If a collection does not exist, MongoDB will automatically create the collection when you first store data for that collection. | | If a collection does not exist, MongoDB will automatically create the collection when you first store data for that collection. |
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| − | You can, however, create one and set some options:
| + | When you first use MongoDB you will find you have no collections: |
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| − | db.createCollection('deptCollection', {max: 20}) | + | show collections |
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| − | In this case we are going to limit our collection to hold a maximum of 20 documents.
| + | When you insert data in the next step, a collection will automatically be created for you. |
| − | | |
| − | == Inserting data ==
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| − | | |
| − | The following example will create a collection representing the DEPT/EMP tables seen in the [[Oracle_Sample_Data|Oracle Sample Data]].
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| − | | |
| − | Add department 10 and it's employees:
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| − | db.deptCollection.insert(
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| − | {
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| − | deptno: 10,
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| − | dname: 'ACCOUNTING',
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| − | loc: 'NEW YORK',
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| − | employees: [
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| − | {
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| − | empno: 7782,
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| − | ename: 'CLARK',
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| − | job: 'MANAGER',
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| − | mgr: 7839,
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| − | hiredate: new Date('1989-06-09'),
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| − | sal: 2450
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| − | },
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| − | {
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| − | empno:7839,
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| − | ename: 'KING',
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| − | job: 'PRESIDENT',
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| − | hiredate: new Date('1980-11-17'),
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| − | sal: 5000
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| − | },
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| − | {
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| − | empno: 7934,
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| − | ename: 'MILLER',
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| − | job: 'CLERK',
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| − | mgr: 7782,
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| − | hiredate: new Date('1985-01-23'),
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| − | sal: 1300
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| − | }
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| − | ]
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| − | }
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| − | )
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| − | | |
| − | Next add department 20:
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| − | | |
| − | db.deptCollection.insert(
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| − | {
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| − | deptno: 20,
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| − | dname: 'RESEARCH',
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| − | loc: 'DALLAS',
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| − | employees: [
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| − | {
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| − | empno: 7876,
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| − | ename: 'ADAMS',
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| − | job: 'CLERK',
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| − | mgr: 7788,
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| − | hiredate: new Date(),
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| − | sal: 1100
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| − | },
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| − | {
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| − | empno: 7902,
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| − | ename: 'FORD',
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| − | job: 'ANALYST',
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| − | mgr: 7566,
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| − | hiredate: new Date('1991-12-03'),
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| − | sal: 3000
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| − | },
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| − | {
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| − | empno: 7066,
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| − | ename: 'JONES',
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| − | job: 'MANAGER',
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| − | mgr: 7839,
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| − | hiredate: new Date('1991-04-02'),
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| − | sal: 2975
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| − | },
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| − | {
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| − | empno: 7788,
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| − | ename: 'SCOTT',
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| − | job: 'ANALYST',
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| − | mgr: 7566,
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| − | hiredate: new Date('2015-10-16'),
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| − | sal: 3000
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| − | }
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| − | ]
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| − | }
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| − | )
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| − | | |
| − | Next department 40, which has no employees currently:
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| − | | |
| − | db.deptCollection.insert(
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| − | {
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| − | deptno: 40,
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| − | dname: 'OPERATIONS',
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| − | loc: 'BOSTON'
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| − | }
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| − | }
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| − | | |
| − | === Things to note ===
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| − | | |
| − | If you are getting errors, check carefully that:
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| − | * every opening bracket has a closing bracket
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| − | * the insert statement uses round brackets: ()
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| − | * an array uses square brackets: []
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| − | * a collection uses curly brackets: {}
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| − | ** each element in a nested collection will also use curly brackets
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| − | * each key:value pair are separated by commas, except for the last item
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| − | * strings are enclosed in single or double quotes, e.g., 'myString', or "myString"
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| − | * date strings are enclosed in single/double quotes and the format is 'yyyy-mm-dd' e.g., Date('2016-10-10')
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| − | * use the Date() constructor to create a date datatype
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| − | * date can also be a datetime, e.g., new Date("<yyyy-mm-ddThh:mm:ss>")
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| − | * new Date() will return the current date
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| − | | |
| − | == Exercise 2.1 ==
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| − | | |
| − | * Compare how you added the above data and how it differs from INSERT records in a relational database
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| − | * Try and add Department 30. Note it has some values for the comm field.
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| | | | |
| | == Next Step == | | == Next Step == |
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| | [[MongoDB_InsertData|Inserting]] data into the collection | | [[MongoDB_InsertData|Inserting]] data into the collection |
Main Page >> MongoDB >>MongoDB Workbook >> Create Collections
Create a Collection
If a collection does not exist, MongoDB will automatically create the collection when you first store data for that collection.
When you first use MongoDB you will find you have no collections:
show collections
When you insert data in the next step, a collection will automatically be created for you.
Next Step
Inserting data into the collection
