Query for get data¶
The read API for queries too long or too private for a URL : the same find, select, sort, skip, limit, deep and getTotalCount as get all, in the body.
| Method | POST |
| URL | /api/schema/admin/mysql8/inventory/customers/query |
| Body | { find, select, sort, skip, limit, deep, getTotalCount } |
| Query params | none |
| Answer | data : an array of rows, totalCount with getTotalCount: true |
| Databases | MongoDB, MySQL, MariaDB, PostgreSQL, SQL Server, Oracle, TiDB, Percona |
| Cached | yes, with enableCaching on the table |
| From code | g.sys.db.query |
| API id | SCHEMA_POST_QUERY (groups, settings, hooks, WebSocket subscriptions) |
| Without a schema | /api/gen/admin/mysql8/inventory/customers/query : below |
Generated (/api/gen) or schema (/api/schema) ?
Both families offer the same operations on the same URL pattern. The schema APIs read the schema of the table : values are converted to their types, validated, encrypted, defaulted and numbered before they reach the database. The generated APIs are schemaless : they pass your data as it is, so a number sent as "22" stays a string. Use the schema APIs for the tables your application writes to, and the generated APIs for quick reads and for tables without a schema.
The URL¶
/api/schema/admin/mysql8/inventory/customers/query : replace admin with the user path of your account, mysql8 with your instance, inventory with the database and customers with the table. The examples use this table :
| customer_id | first_name | last_name | last_update | pincode | isActive |
|---|---|---|---|---|---|
| 1 | Bob | lin | 2022-11-14 04: 34: 58 | 382345 | 1 |
| 2 | Alice | Page | 2022-10-15 02: 10: 40 | 382346 | 1 |
| 3 | Mallory | Brown | 2022-09-13 03: 44: 05 | 382347 | 1 |
| 4 | Eve | Mathly | 2022-11-12 01: 59: 33 | 382348 | 1 |
| 5 | Eve | Page | 2022-11-12 01: 59: 33 | 382349 | 1 |
The body¶
| Key | Meaning |
|---|---|
find |
Required. The filter, with every operator of find. {} for everything. |
select |
Fields to return : "first_name,last_name", "-password", or { first_name: 1 }. |
sort |
"-last_update,first_name" or { last_update: -1 }. |
skip, limit |
Paging. |
deep |
Related rows, see deep. |
getTotalCount |
true adds totalCount, the number of rows matching find before paging. |
{
"find": { "isActive": 1, "pincode": { "$gte": 382345 } },
"select": "customer_id,first_name,last_name",
"sort": "-customer_id",
"skip": 0,
"limit": 10,
"getTotalCount": true
}
{ "success": true, "statusCode": 200, "data": [ { "customer_id": 5, "first_name": "Eve", "last_name": "Page" } ], "totalCount": 5 }
Operators¶
find takes every query operator of MongoDB, and API Maker translates them to SQL where a table can answer them.
| Operator | Example | Meaning |
|---|---|---|
$eq, $ne |
{ "first_name": { "$ne": "Bob" } } |
equal, not equal (a plain value means $eq, null asks for the rows without a value) |
$gt, $gte, $lt, $lte |
{ "pincode": { "$gte": 382345, "$lt": 382349 } } |
comparisons on numbers, strings and ISO dates |
$in, $nin |
{ "customer_id": { "$in": [ 1, 2 ] } } |
in a list, not in a list (an array) |
$and, $or, $nor |
{ "$or": [ { "customer_id": 1 }, { "pincode": 382345 } ] } |
every, any, none of the conditions (an array), inside each other as deep as needed |
$not |
{ "customer_id": { "$not": { "$gt": 3 } } } |
negate the operators |
$exists |
{ "last_update": { "$exists": false } } |
with or without the field (IS NULL on SQL) |
$regex, $options |
{ "first_name": { "$regex": "^ma", "$options": "i" } } |
regular expression |
$mod |
{ "customer_id": { "$mod": [ 2, 0 ] } } |
remainder of a division |
$expr |
{ "$expr": { "$gt": [ "$spent", "$budget" ] } } |
compare fields with each other |
$like |
{ "first_name": { "$like": "Ma%" } } |
SQL like pattern, % and _ |
$isNull |
{ "last_update": { "$isNull": true } } |
null (or not null with false), SQL databases |
- Several operators on one field are all required, on every database :
{ "pincode": { "$gte": 382345, "$lt": 382349 } }. $type,$all,$elemMatch,$size,$text,$where,$jsonSchemaand the geospatial operators are for MongoDB instances ; the bitwise operators work on every database.- See find for every operator, what each one becomes in SQL, and how
nulland regular expressions behave per database.
Find and join¶
A dotted key in find filters on a field of a related table, across databases and instances :
{ "find": { "customer_id.loyalty_tier": "GOLD" } }
- The relation comes from the schema of the table, as many levels as the dots :
"customer_id.city_id.name": "Pune". Adeepitem of the call does not make one, and a virtual field can not be used. - The rows of the related table are read through their own query API, with the permissions of the caller.
- See find and join for every rule.
Deep populate¶
{
"find": {},
"limit": 5,
"deep": [ {
"s_key": "customer_id", "t_col": "orders", "t_key": "customer_id", "isMultiple": true, "select": "order_no,total",
"deep": [ { "s_key": "shipping_id", "t_col": "shippings", "t_key": "id" } ]
} ]
}
- Two items in
deeppopulate two fields ;deepinside an item goes one level further. With relations in the schema,{ "s_key": "customer_id" }is enough.
Types in filters¶
- The values of
findare converted to the types of the schema before the query :"customer_id": "8"matches the number 8.
Caching¶
- With caching on for the table, the same body answers from Redis until a write changes the table.
x-am-cache-control: reset_cacheforces the database.
From your code¶
g.sys.db.query makes the same call from custom APIs, hooks, events, schedulers and test cases, with the same headers and params. To get the whole response envelope instead of data, pass true as the second argument in TypeScript, or call it through g.sys.db.full in the other languages.
Without a schema : /api/gen¶
Every table also answers this operation under /api/gen, with or without a schema :
| URL | /api/gen/admin/mysql8/inventory/customers/query |
| API id | GEN_POST_QUERY (groups, settings, hooks, WebSocket subscriptions) |
| From code | g.sys.db.gen.queryGen |
The data passes as it is : nothing is converted, validated, defaulted, encrypted or numbered, and a filter matches the type you send ("22" does not match the number 22). On MongoDB, strings which look like ObjectIds are converted. The query params, headers and errors are the ones of this page.
Headers¶
Every call takes the request headers : the tokens, x-am-response-case, x-am-content-type-response (JSON, XML, YAML…), x-am-response-object-type: make_flat, x-am-cache-control, x-am-get-encrypted-data, x-am-internationalization, x-am-tenant-username, x-am-meta.
Errors¶
| Code | When |
|---|---|
401 |
The token in x-am-authorization is missing or invalid. |
403 |
No group of the API user grants this API of this table, or a field of the request. |
404 |
The instance, database or table of the URL does not exist, or the table has no schema (use /api/gen). |
400 |
The query or the body is wrong : the error messages say which key and why. |
Related¶
- All APIs at a glance · Query params · Response format · Pre hooks and post hooks · Automatic caching
- Table schema : what the conversions and validations do to every write.