Data Type

Basic Data Type

IoTDB supports the following data types:

• BOOLEAN (Boolean)
• INT32 (Integer)
• INT64 (Long Integer)
• FLOAT (Single Precision Floating Point)
• DOUBLE (Double Precision Floating Point)
• TEXT (Long String)
• STRING（String）
• BLOB（Large binary Object）
• TIMESTAMP（Timestamp）
• DATE（Date）

The difference between STRING and TEXT types is that STRING type has more statistical information and can be used to optimize value filtering queries, while TEXT type is suitable for storing long strings.

Float Precision

The time series of FLOAT and DOUBLE type can specify (MAX_POINT_NUMBER, see this page for more information on how to specify), which is the number of digits after the decimal point of the floating point number, if the encoding method is RLE or TS_2DIFF. If MAX_POINT_NUMBER is not specified, the system will use float_precision in the configuration file iotdb-system.properties.

CREATE TIMESERIES root.vehicle.d0.s0 WITH DATATYPE=FLOAT, ENCODING=RLE, 'MAX_POINT_NUMBER'='2';

• For Float data value, The data range is (-Integer.MAX_VALUE, Integer.MAX_VALUE), rather than Float.MAX_VALUE, and the max_point_number is 19, caused by the limitation of function Math.round(float) in Java.
• For Double data value, The data range is (-Long.MAX_VALUE, Long.MAX_VALUE), rather than Double.MAX_VALUE, and the max_point_number is 19, caused by the limitation of function Math.round(double) in Java (Long.MAX_VALUE=9.22E18).

Data Type Compatibility

When the written data type is inconsistent with the data type of time-series,

• If the data type of time-series is not compatible with the written data type, the system will give an error message.
• If the data type of time-series is compatible with the written data type, the system will automatically convert the data type.

The compatibility of each data type is shown in the following table:

Series Data Type	Supported Written Data Types
BOOLEAN	BOOLEAN
INT32	INT32
INT64	INT32 INT64
FLOAT	INT32 FLOAT
DOUBLE	INT32 INT64 FLOAT DOUBLE
TEXT	TEXT

Timestamp

The timestamp is the time point at which data is produced. It includes absolute timestamps and relative timestamps

Absolute timestamp

Absolute timestamps in IoTDB are divided into two types: LONG and DATETIME (including DATETIME-INPUT and DATETIME-DISPLAY). When a user inputs a timestamp, he can use a LONG type timestamp or a DATETIME-INPUT type timestamp, and the supported formats of the DATETIME-INPUT type timestamp are shown in the table below:

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Supported formats of DATETIME-INPUT type timestamp

Format
yyyy-MM-dd HH:mm:ss
yyyy/MM/dd HH:mm:ss
yyyy.MM.dd HH:mm:ss
yyyy-MM-dd HH:mm:ssZZ
yyyy/MM/dd HH:mm:ssZZ
yyyy.MM.dd HH:mm:ssZZ
yyyy/MM/dd HH:mm:ss.SSS
yyyy-MM-dd HH:mm:ss.SSS
yyyy.MM.dd HH:mm:ss.SSS
yyyy-MM-dd HH:mm:ss.SSSZZ
yyyy/MM/dd HH:mm:ss.SSSZZ
yyyy.MM.dd HH:mm:ss.SSSZZ
ISO8601 standard time format

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IoTDB can support LONG types and DATETIME-DISPLAY types when displaying timestamps. The DATETIME-DISPLAY type can support user-defined time formats. The syntax of the custom time format is shown in the table below:

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The syntax of the custom time format

Symbol	Meaning	Presentation	Examples
G	era	era	era
C	century of era (>=0)	number	20
Y	year of era (>=0)	year	1996
x	weekyear	year	1996
w	week of weekyear	number	27
e	day of week	number	2
E	day of week	text	Tuesday; Tue
y	year	year	1996
D	day of year	number	189
M	month of year	month	July; Jul; 07
d	day of month	number	10
a	halfday of day	text	PM
K	hour of halfday (0~11)	number	0
h	clockhour of halfday (1~12)	number	12
H	hour of day (0~23)	number	0
k	clockhour of day (1~24)	number	24
m	minute of hour	number	30
s	second of minute	number	55
S	fraction of second	millis	978
z	time zone	text	Pacific Standard Time; PST
Z	time zone offset/id	zone	-0800; -08:00; America/Los_Angeles
'	escape for text	delimiter
''	single quote	literal	'

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Relative timestamp

Relative time refers to the time relative to the server time now() and DATETIME time.

Syntax:

Duration = (Digit+ ('Y'|'MO'|'W'|'D'|'H'|'M'|'S'|'MS'|'US'|'NS'))+
RelativeTime = (now() | DATETIME) ((+|-) Duration)+

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The syntax of the duration unit

Symbol	Meaning	Presentation	Examples
y	year	1y=365 days	1y
mo	month	1mo=30 days	1mo
w	week	1w=7 days	1w
d	day	1d=1 day	1d
h	hour	1h=3600 seconds	1h
m	minute	1m=60 seconds	1m
s	second	1s=1 second	1s
ms	millisecond	1ms=1000_000 nanoseconds	1ms
us	microsecond	1us=1000 nanoseconds	1us
ns	nanosecond	1ns=1 nanosecond	1ns

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eg：

now() - 1d2h //1 day and 2 hours earlier than the current server time
now() - 1w //1 week earlier than the current server time

Note：There must be spaces on the left and right of '+' and '-'.