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Model management tools for the oVirt Engine API.
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[appendix]
== Primitive types

This section describes the primitive data types supported by the API.

[id="types/string"]
=== String [small]#primitive#

A finite sequence of http://unicode.org[Unicode] characters.

[id="types/boolean"]
=== Boolean [small]#primitive#

Represents the _false_ and _true_ concepts used in mathematical logic.

The valid values are the strings `false` and `true`.

Case is ignored by the engine, so for example `False` and `FALSE` also
valid values. However the server will always return lower case values.

For backwards compatibility with older versions of the engine, the
values `0` and `1` are also accepted. The value `0` has the same meaning
than `false`, and `1` has the same meaning than `true`. Try to avoid
using these values, as support for them may be removed in the future.

[id="types/integer"]
=== Integer [small]#primitive#

Represents the mathematical concept of integer number.

The valid values are finite sequences of decimal digits.

Currently the engine implements this type using a signed 32 bit
integer, so the minimum value is -2^31^ (-2147483648) and the maximum
value is 2^31^-1 (2147483647).

However, there are some attributes in the system where the range of
values possible with 32 bit isn't enough. In those exceptional cases
the engine uses 64 bit integers, in particular for the following
attributes:

- `Disk.actual_size`
- `Disk.provisioned_size`
- `GlusterClient.bytes_read`
- `GlusterClient.bytes_written`
- `Host.max_scheduling_memory`
- `Host.memory`
- `HostNic.speed`
- `LogicalUnit.size`
- `MemoryPolicy.guaranteed`
- `NumaNode.memory`
- `QuotaStorageLimit.limit`
- `StorageDomain.available`
- `StorageDomain.used`
- `StorageDomain.committed`
- `VmBase.memory`

For these exception cases the minimum value is -2^63^
(-9223372036854775808) and the maximum value is 2^63^-1
(9223372036854775807).

NOTE: In the future the integer type will be implemented using
unlimited precission integers, so the above limitations and exceptions
will eventually disappear.

[id="types/decimal"]
=== Decimal [small]#primitive#

Represents the mathematical concept of real number.

Currently the engine implements this type using 32 bit
https://en.wikipedia.org/wiki/IEEE_floating_point[IEEE 754] single
precision floating point numbers.

For some attributes this isn't enough precision. In those exceptional
cases the engine uses 64 bit double precision floating point numbers,
in particular for the following attributes:

- `QuotaStorageLimit.usage`
- `QuotaStorageLimit.memory_limit`
- `QuotaStorageLimit.memory_usage`

NOTE: In the future the decimal type will be implemented using unlimited
precision decimal numbers, so the above limitations and exceptions will
eventually disappear.

[id="types/date"]
=== Date [small]#primitive#

Represents a date and time.

The format returned by the engine is the one described in the
https://www.w3.org/TR/xmlschema11-2/#dateTime[XML Schema specification]
when requesting XML. For example, if you send a request like this to
retrieve the XML representation of a virtual machine:

[source]
----
GET /ovirt-engine/api/vms/123
Accept: application/xml
----

The response body will contain the following XML document:

[source,xml]
----

  ...
  2016-09-08T09:53:35.138+02:00
  ...

----

When requesting the JSON representation the engine uses a different,
format: an integer containing the number of milliseconds since Jan 1^st^ 1970,
also known as https://en.wikipedia.org/wiki/Unix_time[_epoch time_]. For
example, if you send a request like this to retrieve the JSON
representation of a virtual machine:

[source]
----
GET /ovirt-engine/api/vms/123
Accept: application/json
----

The response body will contain the following JSON document:

[source,json]
----
{
  "id": "123",
  "href="/ovirt-engine/api/vms/123",
  ...
  "creation_time": 1472564909990,
  ...
}
----

NOTE: In both cases, the dates returned by the engine use the time zone
configured in the server where it is running, in the above examples it
is UTC+2.