Data Type

1. Basic Data Types

IoTDB supports the following ten data types:

• BOOLEAN (Boolean value)
• INT32 (32-bit integer)
• INT64 (64-bit integer)
• FLOAT (Single-precision floating-point number)
• DOUBLE (Double-precision floating-point number)
• TEXT (Text data, suitable for long strings)
• STRING (String data with additional statistical information for optimized queries)
• BLOB (Large binary object)
• TIMESTAMP (Timestamp, representing precise moments in time)
• DATE (Date, storing only calendar date information)

The difference between STRING and TEXT:

• STRING stores text data and includes additional statistical information to optimize value-filtering queries.
• TEXT is suitable for storing long text strings without additional query optimization.

1.1 Floating-Point Precision Configuration

For FLOAT and DOUBLE series using RLE or TS_2DIFF encoding, the number of decimal places can be set via the MAX_POINT_NUMBER attribute during series creation.

For example:

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

If not specified, the system will use the configuration in the iotdb-system.properties file under the float_precision item (default is 2 decimal places).

1.2 Data Type Compatibility

If the written data type does not match the registered data type of a series:

• Incompatible types → The system will issue an error.
• Compatible types → The system will automatically convert the written data type to match the registered type.

The compatibility of data types is shown in the table below:

Registered Data Type	Compatible Write Data Types
BOOLEAN	BOOLEAN
INT32	INT32
INT64	INT32, INT64, TIMESTAMP
FLOAT	INT32, FLOAT
DOUBLE	INT32, INT64, FLOAT, DOUBLE, TIMESTAMP
TEXT	TEXT, STRING
STRING	TEXT, STRING
BLOB	TEXT, STRING, BLOB
TIMESTAMP	INT32, INT64, TIMESTAMP
DATE	DATE

2. Timestamp Types

A timestamp represents the moment when data is recorded. IoTDB supports two types:

• Absolute timestamps: Directly specify a point in time.
• Relative timestamps: Define time offsets from a reference point (e.g., now()).

2.1 Absolute Timestamp

IoTDB supports timestamps in two formats:

1. LONG: Milliseconds since the Unix epoch (1970-01-01 00:00:00 UTC).
2. DATETIME: Human-readable date-time strings. (including DATETIME-INPUT and DATETIME-DISPLAY subcategories).

When entering a timestamp, users can use either a LONG value or a DATETIME string. Supported input formats include:

DATETIME-INPUT Type Supports Format

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

Note: ZZ represents a time zone offset (e.g., +0800 for Beijing Time, -0500 for Eastern Standard Time).

IoTDB supports timestamp display in LONG format or DATETIME-DISPLAY format, allowing users to customize time output.

Syntax for Custom Time Formats in DATETIME-DISPLAY

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	'

2.2 Relative Timestamp

Relative timestamps allow specifying time offsets from now() or a DATETIME reference.

The formal definition is:

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

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

Examples:

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

Note: There must be spaces on both sides of + and - operators.