# Database API
Mini Program Cloud Base provides a rich set of database APIs. Here is the API reference documentation for the database Server. It can be used in a cloud function environment.
Server APIs are almost the same as the Mini Program APIs except for the followings:
- Server APIs no longer accept callback (
success
,fail
, andcomplete
) but all returnPromise
. - The Server has bulk write and bulk delete permissions. This means that
update
orremove
can be called in a collection or query statement. - Unique server APIs, such as the API for collection creation (db.createCollection).
Database APIs use lazy execution, which means that only API calls that actually require a network request can initiate a network request, and other calls, such as getting a database, collection, record reference, and constructing a query condition on a collection, cannot trigger a network request. The APIs that trigger network requests are as follows:
API | Description |
---|---|
get | Gets data collection/record data |
add | Adds a record to the collection |
update | Updates data collection/record data |
set | Replaces and updates a record |
remove | Deletes record |
count | Counts the number of records matched to the query statement |
The APIs to get reference are as follows:
API | Description |
---|---|
database | Gets a database reference, and the Database object is returned |
collection | Gets a collection reference, and the Collection object is returned |
doc | Gets a record reference, and the Document object is returned |
The "Database" object has the following fields:
Field | Description |
---|---|
command | Gets database query and update commands, and Command is returned |
serverDate | Constructs a server time |
Geo | Gets a geographical location operation object, and the Geo object is returned |
createCollection | Create a collection |
The "Collection" object has the following APIs:
API | Description |
---|---|
doc | Gets a record reference, and the Document object is returned |
add | Adds a record to the collection |
update | Update data |
where | Constructs a query condition on the current collection, and Query is returned. Query commands can be used in the query condition. |
remove | Delete records that match the filter criteria |
orderBy | Specifies the sort order of query data |
limit | Specifies the maximum amount of return data |
skip | Specifies the item in the matched record list after which the result is returned when you perform a query |
field | Specifies the fields that should be included in each record in the return result |
The "Document" object has the following APIs:
API | Description |
---|---|
get | Gets record data |
update | Locally updates data |
set | Replaces and updates record |
remove | Deletes record |
field | Specifies the fields that should be included in the record of the return result |
The Command (db.command
) object has the following query commands:
API | Description |
---|---|
eq | Indicates whether the field value is equal to the specified value |
neq | Indicates whether the field value is not equal to the specified value |
lt | Indicates whether the field value is less than the specified value |
lte | Indicates whether the field value is less than or equal to the specified value |
gt | Indicates whether the field value is greater than the specified value |
gte | Indicates whether the field value is greater than or equal to the specified value |
in | Indicates whether the field value is in the specified array |
nin | Indicates whether the field value is in the specified array |
and | The condition "and" means that another condition must be met at the same time |
or | The condition "or" means that another condition may be met |
The Command (db.command
) object has the following update commands:
API | Description |
---|---|
set | Sets the field as specified value |
remove | Deletes field |
inc | Atomic auto-incrementing field value |
mul | Atomic auto-multiplying field value |
push | If the field value is an array, add a specified value to the end of the array |
pop | If the field value is an array, delete an element from the end of the array |
shift | If the field value is an array, delete an element from the head of the array |
unshift | If the field value is an array, add the specified value to the head of the array |
The object of Error
returned from API reject
has the following two fields.
Field | Type | Description |
---|---|---|
errCode | number | Error Codes |
errMsg | string | Error message |