An instance of Asterix data model (ADM) can be a primitive type (boolean
, tinyint
, smallint
, integer
, bigint
, string
, float
, double
, date
, time
, datetime
, etc.), a special type (null
or missing
), or a derived type.
The type names are case-insensitive, e.g., both BIGINT
and bigint
are acceptable.
boolean
data type can have one of the two values: true or false.
Example:
{ "true": true, "false": false };
The expected result is:
{ "true": true, "false": false }
Integer types using 8, 16, 32, or 64 bits. The ranges of these types are:
tinyint
: -127 to 127smallint
: -32767 to 32767integer
: -2147483647 to 2147483647bigint
: -9223372036854775808 to 9223372036854775807int
is an abbreviated alias for integer.
Example:
{ "tinyint": tiny("125"), "smallint": smallint("32765"), "integer": 294967295, "bigint": bigint("1700000000000000000")};
The expected result is:
{ "tinyint": 125, "smallint": 32765, "integer": 294967295, "bigint": 17000000 }
float
represents approximate numeric data values using 4 bytes. The range of a float value can be from 2^(-149) to (2-2^(-23)·2^(127) for both positive and negative. Beyond these ranges will get INF
or -INF
.
Example:
{ "v1": float("NaN"), "v2": float("INF"), "v3": float("-INF"), "v4": float("-2013.5") };
The expected result is:
{ "v1": NaN, "v2": Infinity, "v3": -Infinity, "v4": -2013.5 }
double
represents approximate numeric data values using 8 bytes. The range of a double value can be from (2^(-1022)) to (2-2^(-52))·2^(1023) for both positive and negative. Beyond these ranges will get INF
or -INF
.
Example:
{ "v1": double("NaN"), "v2": double("INF"), "v3": double("-INF"), "v4": "-2013.593823748327284" };
The expected result is:
{ "v1": NaN, "v2": Infinity, "v3": -Infinity, "v4": -2013.5938237483274 }
Double precision
is an alias of double
.
string
represents a sequence of characters. The total length of the sequence can be up to 2,147,483,648.
Example:
{ "v1": string("This is a string."), "v2": string("\"This is a quoted string\"") };
The expected result is:
{ "v1": "This is a string.", "v2": "\"This is a quoted string\"" }
binary
represents a sequence of bytes. It can be constructed from a hex
or a base64
string sequence. The total length of the byte sequence can be up to 2,147,483,648.
Example:
{ "hex1" : hex("ABCDEF0123456789"), "hex2": hex("abcdef0123456789"), "base64_1" : base64("0123456789qwertyui+/"), "base64_2" : base64('QXN0ZXJpeA==') };
The default output format is in hex
format. Thus, the expected result is:
{ "hex1": hex("ABCDEF0123456789"), "hex2": hex("ABCDEF0123456789"), "base64_1": hex("D35DB7E39EBBF3DAB07ABB72BA2FBF"), "base64_2": hex("41737465726978") }
point
is the fundamental two-dimensional building block for spatial types. It consists of two double
coordinates x and y.
Example:
{ "v1": point("80.10d, -10E5"), "v2": point("5.10E-10d, -10E5") };
The expected result is:
{ "v1": point("80.1,-1000000.0"), "v2": point("5.1E-10,-1000000.0") }
line
consists of two points that represent the start and the end points of a line segment.
Example:
{ "v1": line("10.1234,11.1e-1 +10.2E-2,-11.22"), "v2": line("0.1234,-1.00e-10 +10.5E-2,-01.02") };
The expected result is:
{ "v1": line("10.1234,1.11 0.102,-11.22"), "v2": line("0.1234,-1.0E-10 0.105,-1.02") }
rectangle
consists of two points that represent the bottom left and upper right corners of a rectangle.
Example:
{ "v1": rectangle("5.1,11.8 87.6,15.6548"), "v2": rectangle("0.1234,-1.00e-10 5.5487,0.48765") };
The expected result is:
{ "v1": rectangle("5.1,11.8 87.6,15.6548"), "v2": rectangle("0.1234,-1.0E-10 5.5487,0.48765") }
circle
consists of one point that represents the center of the circle and a radius of type double
.
Example:
{ "v1": circle("10.1234,11.1e-1 +10.2E-2"), "v2": circle("0.1234,-1.00e-10 +10.5E-2") };
The expected result is:
{ "v1": circle("10.1234,1.11 0.102"), "v2": circle("0.1234,-1.0E-10 0.105") }
polygon
consists of n points that represent the vertices of a simple closed polygon.
Example:
{ "v1": polygon("-1.2,+1.3e2 -2.14E+5,2.15 -3.5e+2,03.6 -4.6E-3,+4.81"), "v2": polygon("-1.0,+10.5e2 -02.15E+50,2.5 -1.0,+3.3e3 -2.50E+05,20.15 +3.5e+2,03.6 -4.60E-3,+4.75 -2,+1.0e2 -2.00E+5,20.10 30.5,03.25 -4.33E-3,+4.75") };
The expected result is:
{ "v1": polygon("-1.2,130.0 -214000.0,2.15 -350.0,3.6 -0.0046,4.81"), "v2": polygon("-1.0,1050.0 -2.15E50,2.5 -1.0,3300.0 -250000.0,20.15 350.0,3.6 -0.0046,4.75 -2.0,100.0 -200000.0,20.1 30.5,3.25 -0.00433,4.75") } }
date
represents a time point along the Gregorian calendar system specified by the year, month and day. ASTERIX supports the date from -9999-01-01
to 9999-12-31
.
A date value can be represented in two formats, extended format and basic format.
Extended format is represented as [-]yyyy-mm-dd
for year-month-day
. Each field should be padded if there are less digits than the format specified.
Basic format is in the format of [-]yyyymmdd
.
Example:
{ "v1": date("2013-01-01"), "v2": date("-19700101") };
The expected result is:
{ "v1": date("2013-01-01"), "v2": date("-1970-01-01") }
time
type describes the time within the range of a day. It is represented by three fields: hour, minute and second. Millisecond field is optional as the fraction of the second field. Its extended format is as hh:mm:ss[.mmm]
and the basic format is hhmmss[mmm]
. The value domain is from 00:00:00.000
to 23:59:59.999
.
Timezone field is optional for a time value. Timezone is represented as [+|-]hh:mm
for extended format or [+|-]hhmm
for basic format. Note that the sign designators cannot be omitted. Z
can also be used to represent the UTC local time. If no timezone information is given, it is UTC by default.
Example:
{ "v1": time("12:12:12.039Z"), "v2": time("000000000-0800") };
The expected result is:
{ "v1": time("12:12:12.039Z"), "v2": time("08:00:00.000Z") }
A datetime
value is a combination of an date
and time
, representing a fixed time point along the Gregorian calendar system. The value is among -9999-01-01 00:00:00.000
and 9999-12-31 23:59:59.999
.
A datetime
value is represented as a combination of the representation of its date
part and time
part, separated by a separator T
. Either extended or basic format can be used, and the two parts should be the same format.
Millisecond field and timezone field are optional, as specified in the time
type.
Example:
{ "v1": datetime("2013-01-01T12:12:12.039Z"), "v2": datetime("-19700101T000000000-0800") };
The expected result is:
{ "v1": datetime("2013-01-01T12:12:12.039Z"), "v2": datetime("-1970-01-01T08:00:00.000Z") }
timestamp
is an alias of datetime
.
duration
represents a duration of time. A duration value is specified by integers on at least one of the following fields: year, month, day, hour, minute, second, and millisecond.
A duration value is in the format of [-]PnYnMnDTnHnMn.mmmS
. The millisecond part (as the fraction of the second field) is optional, and when no millisecond field is used, the decimal point should also be absent.
Negative durations are also supported for the arithmetic operations between time instance types (date
, time
and datetime
), and is used to roll the time back for the given duration. For example date("2012-01-01") + duration("-P3D")
will return date("2011-12-29")
.
There are also two sub-duration types, namely year_month_duration
and day_time_duration
. year_month_duration
represents only the years and months of a duration, while day_time_duration
represents only the day to millisecond fields. Different from the duration
type, both these two subtypes are totally ordered, so they can be used for comparison and index construction.
Note that a canonical representation of the duration is always returned, regardless whether the duration is in the canonical representation or not from the user's input. More information about canonical representation can be found from XPath dayTimeDuration Canonical Representation and yearMonthDuration Canonical Representation.
Example:
{ "v1": duration("P100Y12MT12M"), "v2": duration("-PT20.943S") };
The expected result is:
{ "v1": duration("P101YT12M"), "v2": duration("-PT20.943S") }
interval
represents inclusive-exclusive ranges of time. It is defined by two time point values with the same temporal type(date
, time
or datetime
).
Example:
{ "v1": interval(date("2013-01-01"), date("20130505")), "v2": interval(time("00:01:01"), time("213901049+0800")), "v3": interval(datetime("2013-01-01T00:01:01"), datetime("20130505T213901049+0800")) };
The expected result is:
{ "v1": interval(date("2013-01-01"), date("2013-05-05")), "v2": interval(time("00:01:01.000Z"), time("13:39:01.049Z")), "v3": interval(datetime("2013-01-01T00:01:01.000Z"), datetime("2013-05-05T13:39:01.049Z")) }
uuid
represents a UUID value, which stands for Universally unique identifier. It is defined by a canonical format using hexadecimal text with inserted hyphen characters. (E.g.: 5a28ce1e-6a74-4201-9e8f-683256e5706f). This type is generally used to store auto-generated primary key values.
Example:
return { "v1":uuid("5c848e5c-6b6a-498f-8452-8847a2957421") }
The expected result is:
{ "v1": uuid("5c848e5c-6b6a-498f-8452-8847a2957421") }
null
is a special value that is often used to represent an unknown value. For example, a user might not be able to know the value of a field and let it be null
.
Example:
{ "field": null };
The expected result is:
{ "field": null }
missing
represents a missing name-value pair in a record. If the referenced field does not exist, an empty result value is returned by the query.
As neither the data model nor the system enforces homogeneity for datasets or collections, items in a dataset or collection can be of heterogeneous types and so a field can be present in one record and missing
in another.
Example:
{ "field": missing };
The expected result is:
{ }
Since a field with value missing
means the field is absent, we get an empty record.
A record
contains a set of fields, where each field is described by its name and type. A record type is either open or closed. Open records can contain fields that are not part of the type definition, while closed records cannot. Syntactically, record constructors are surrounded by curly braces “{...}”.
An example would be
{ "id": 213508, "name": "Alice Bob" }
An array
is a container that holds a fixed number of values. Array constructors are denoted by brackets: “[...]”.
An example would be
["alice", 123, "bob", null]
A multiset
is a generalization of the concept of a set that, unlike a set, allows multiple instances of the multiset's elements. Multiset constructors are denoted by two opening curly braces followed by data and two closing curly braces, like “{{...}}”.
An example would be
{{"hello", 9328, "world", [1, 2, null]}}