Gráfico de mapeamento SQL para MongoDB

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Terminology and Concepts
Executables
Exemplos
Leitura adicional

In addition to the charts that follow, you might want to consider the Perguntas frequentes section for a selection of common questions about MongoDB.

Terminology and Concepts

The following table presents the various SQL terminology and concepts and the corresponding MongoDB terminology and concepts.

SQL Terms/Concepts	MongoDB Terms/Concepts
database	database
table	collection
row	documento ou BSON document
column	Campo
index	index
table joins	`$lookup`, embedded documents
chave primária Specify any unique column or column combination as primary key.	chave primária In MongoDB, the primary key is automatically set to the _id field.
aggregation (e.g. group by)	aggregation pipeline See the Gráfico de mapeamento SQL para agregação.
SELECIONAR EM NEW_TABLE	`$out` See the Gráfico de mapeamento SQL para agregação.
MESCLAR NA TABELA	`$merge` See the Gráfico de mapeamento SQL para agregação.
UNION ALL	`$unionWith`
transações	transações For many scenarios, the denormalized data model (embedded documents and arrays) will continue to be optimal for your data and use cases instead of multi-document transactions. That is, for many scenarios, modeling your data appropriately will minimize the need for multi-document transactions.

Executables

The following table presents some database executables and the corresponding MongoDB executables. This table is não meant to be exhaustive.

	MongoDB	MySQL	Oracle	Informix	DB2
Database Server	`mongod`	`mysqld`	`oracle`	`IDS`	`DB2 Server`
Database Client	`mongosh`	`mysql`	`sqlplus`	`DB-Access`	`DB2 Client`

Exemplos

The following table presents the various SQL statements and the corresponding MongoDB statements. The examples in the table assume the following conditions:

The SQL examples assume a table named people.
The MongoDB examples assume a collection named people that contain documents of the following prototype:
```
{
  _id: ObjectId("509a8fb2f3f4948bd2f983a0"),
  user_id: "abc123",
  age: 55,
  status: 'A'
}
```

Create and Alter

The following table presents the various SQL statements related to table-level actions and the corresponding MongoDB statements.

SQL Schema Statements

MongoDB Schema Statements

CREATE TABLE people (
    id MEDIUMINT NOT NULL
        AUTO_INCREMENT,
    user_id Varchar(30),
    age Number,
    status char(1),
    PRIMARY KEY (id)
)

Implicitly created on first insertOne() or insertMany() operation. The primary key _id is automatically added if _id field is not specified.

db.people.insertOne( {
    user_id: "abc123",
    age: 55,
    status: "A"
 } )

However, you can also explicitly create a collection:

db.createCollection("people")

ALTER TABLE people
ADD join_date DATETIME

Collections do not describe or enforce the structure of its documents; i.e. there is no structural alteration at the collection level.

However, at the document level, updateMany() operations can add fields to existing documents using the $set operator.

db.people.updateMany(
    { },
    { $set: { join_date: new Date() } }
)

ALTER TABLE people
DROP COLUMN join_date

Collections do not describe or enforce the structure of its documents; i.e. there is no structural alteration at the collection level.

However, at the document level, updateMany() operations can remove fields from documents using the $unset operator.

db.people.updateMany(
    { },
    { $unset: { "join_date": "" } }
)

CREATE INDEX idx_user_id_asc
ON people(user_id)

db.people.createIndex( { user_id: 1 } )

CREATE INDEX
       idx_user_id_asc_age_desc
ON people(user_id, age DESC)

db.people.createIndex( { user_id: 1, age: -1 } )

DROP TABLE people

db.people.drop()

For more information on the methods and operators used, see:

Veja também:

Insert

The following table presents the various SQL statements related to inserting records into tables and the corresponding MongoDB statements.

SQL INSERT Statements

MongoDB insertOne() Statements

INSERT INTO people(user_id,
                  age,
                  status)
VALUES ("bcd001",
        45,
        "A")

db.people.insertOne(
   { user_id: "bcd001", age: 45, status: "A" }
)

Para mais informações, consulte db.collection.insertOne().

Veja também:

Select

The following table presents the various SQL statements related to reading records from tables and the corresponding MongoDB statements.

Observação

The find() method always includes the _id field in the returned documents unless specifically excluded through projeção. Some of the SQL queries below may include an _id field to reflect this, even if the field is not included in the corresponding find() query.

SQL SELECT Statements

MongoDB find() Statements

SELECT *
FROM people

db.people.find()

SELECT id,
       user_id,
       status
FROM people

db.people.find(
    { },
    { user_id: 1, status: 1 }
)

SELECT user_id, status
FROM people

db.people.find(
    { },
    { user_id: 1, status: 1, _id: 0 }
)

SELECT *
FROM people
WHERE status = "A"

db.people.find(
    { status: "A" }
)

SELECT user_id, status
FROM people
WHERE status = "A"

db.people.find(
    { status: "A" },
    { user_id: 1, status: 1, _id: 0 }
)

SELECT *
FROM people
WHERE status != "A"

db.people.find(
    { status: { $ne: "A" } }
)

SELECT *
FROM people
WHERE status = "A"
AND age = 50

db.people.find(
    { status: "A",
      age: 50 }
)

SELECT *
FROM people
WHERE status = "A"
OR age = 50

db.people.find(
    { $or: [ { status: "A" } , { age: 50 } ] }
)

SELECT *
FROM people
WHERE age > 25

db.people.find(
    { age: { $gt: 25 } }
)

SELECT *
FROM people
WHERE age < 25

db.people.find(
   { age: { $lt: 25 } }
)

SELECT *
FROM people
WHERE age > 25
AND   age <= 50

db.people.find(
   { age: { $gt: 25, $lte: 50 } }
)

SELECT *
FROM people
WHERE user_id like "%bc%"

db.people.find( { user_id: /bc/ } )

-ou-

db.people.find( { user_id: { $regex: /bc/ } } )

SELECT *
FROM people
WHERE user_id like "bc%"

db.people.find( { user_id: /^bc/ } )

-ou-

db.people.find( { user_id: { $regex: /^bc/ } } )

SELECT *
FROM people
WHERE status = "A"
ORDER BY user_id ASC

db.people.find( { status: "A" } ).sort( { user_id: 1 } )

SELECT *
FROM people
WHERE status = "A"
ORDER BY user_id DESC

db.people.find( { status: "A" } ).sort( { user_id: -1 } )

SELECT COUNT(*)
FROM people

db.people.count()

db.people.find().count()

SELECT COUNT(user_id)
FROM people

db.people.count( { user_id: { $exists: true } } )

db.people.find( { user_id: { $exists: true } } ).count()

SELECT COUNT(*)
FROM people
WHERE age > 30

db.people.count( { age: { $gt: 30 } } )

db.people.find( { age: { $gt: 30 } } ).count()

SELECT DISTINCT(status)
FROM people

db.people.aggregate( [ { $group : { _id : "$status" } } ] )

or, for distinct value sets that do not exceed the BSON size limit

db.people.distinct( "status" )

SELECT *
FROM people
LIMIT 1

db.people.findOne()

db.people.find().limit(1)

SELECT *
FROM people
LIMIT 5
SKIP 10

db.people.find().limit(5).skip(10)

EXPLAIN SELECT *
FROM people
WHERE status = "A"

db.people.find( { status: "A" } ).explain()

For more information on the methods and operators used, see

Veja também:

Update Records

The following table presents the various SQL statements related to updating existing records in tables and the corresponding MongoDB statements.

SQL Update Statements

MongoDB updateMany() Statements

UPDATE people
SET status = "C"
WHERE age > 25

db.people.updateMany(
   { age: { $gt: 25 } },
   { $set: { status: "C" } }
)

UPDATE people
SET age = age + 3
WHERE status = "A"

db.people.updateMany(
   { status: "A" } ,
   { $inc: { age: 3 } }
)

For more information on the method and operators used in the examples, see:

Veja também:

Delete Records

The following table presents the various SQL statements related to deleting records from tables and the corresponding MongoDB statements.

SQL Delete Statements

MongoDB deleteMany() Statements

DELETE FROM people
WHERE status = "D"

db.people.deleteMany( { status: "D" } )

DELETE FROM people

db.people.deleteMany({})

Para mais informações, consulte db.collection.deleteMany().

Veja também:

Leitura adicional

If you are considering migrating your SQL application to MongoDB, download the MongoDB Application Modernization Guide.

O download inclui os seguintes recursos:

Apresentação sobre a metodologia de modelagem de dados com o MongoDB
Artigo técnico que aborda as melhores práticas e considerações para migrar de um modelo de dados SGBD para o MongoDB
Referenciar o esquema do MongoDB com seu equivalente em SGBD
Scorecard de modernização de aplicativos

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