Data Types

Due to historical reasons, before Flink 1.9, Flink’s Table & SQL API data types weretightly coupled to Flink’s TypeInformation. TypeInformation is used in the DataStreamand DataSet API and is sufficient to describe all information needed to serialize anddeserialize JVM-based objects in a distributed setting.

However, TypeInformation was not designed to represent logical types independent ofan actual JVM class. In the past, it was difficult to map SQL standard types to thisabstraction. Furthermore, some types were not SQL-compliant and introduced without abigger picture in mind.

Starting with Flink 1.9, the Table & SQL API will receive a new type system that serves as a long-termsolution for API stability and standard compliance.

Reworking the type system is a major effort that touches almost all user-facing interfaces. Therefore, itsintroduction spans multiple releases, and the community aims to finish this effort by Flink 1.10.

Due to the simultaneous addition of a new planner for table programs (see FLINK-11439),not every combination of planner and data type is supported. Furthermore, planners might not support everydata type with the desired precision or parameter.

Attention Please see the planner compatibility table and limitationssection before using a data type.

Data Type

A data type describes the logical type of a value in the table ecosystem. It can be used to declare input and/oroutput types of operations.

Flink’s data types are similar to the SQL standard’s data type terminology but also contain informationabout the nullability of a value for efficient handling of scalar expressions.

Examples of data types are:

  • INT
  • INT NOT NULL
  • INTERVAL DAY TO SECOND(3)
  • ROW<myField ARRAY<BOOLEAN>, myOtherField TIMESTAMP(3)>A list of all pre-defined data types can be found below.

Data Types in the Table API

Users of the JVM-based API work with instances of org.apache.flink.table.types.DataType within the Table API or whendefining connectors, catalogs, or user-defined functions.

A DataType instance has two responsibilities:

  • Declaration of a logical type which does not imply a concrete physical representation for transmissionor storage but defines the boundaries between JVM-based languages and the table ecosystem.
  • Optional:Giving hints about the physical representation of data to the planner which is useful at the edges to other APIs .For JVM-based languages, all pre-defined data types are available in org.apache.flink.table.api.DataTypes.

It is recommended to add a star import to your table programs for having a fluent API:

  1. import static org.apache.flink.table.api.DataTypes.*;
  2. DataType t = INTERVAL(DAY(), SECOND(3));
  1. import org.apache.flink.table.api.DataTypes._
  2. val t: DataType = INTERVAL(DAY(), SECOND(3));

Physical Hints

Physical hints are required at the edges of the table ecosystem where the SQL-based type system ends andprogramming-specific data types are required. Hints indicate the data format that an implementationexpects.

For example, a data source could express that it produces values for logical TIMESTAMPs using a java.sql.Timestamp classinstead of using java.time.LocalDateTime which would be the default. With this information, the runtime is able to convertthe produced class into its internal data format. In return, a data sink can declare the data format it consumes from the runtime.

Here are some examples of how to declare a bridging conversion class:

  1. // tell the runtime to not produce or consume java.time.LocalDateTime instances
  2. // but java.sql.Timestamp
  3. DataType t = DataTypes.TIMESTAMP(3).bridgedTo(java.sql.Timestamp.class);
  4. // tell the runtime to not produce or consume boxed integer arrays
  5. // but primitive int arrays
  6. DataType t = DataTypes.ARRAY(DataTypes.INT().notNull()).bridgedTo(int[].class);
  1. // tell the runtime to not produce or consume java.time.LocalDateTime instances
  2. // but java.sql.Timestamp
  3. val t: DataType = DataTypes.TIMESTAMP(3).bridgedTo(classOf[java.sql.Timestamp]);
  4. // tell the runtime to not produce or consume boxed integer arrays
  5. // but primitive int arrays
  6. val t: DataType = DataTypes.ARRAY(DataTypes.INT().notNull()).bridgedTo(classOf[Array[Int]]);

Attention Please note that physical hints are usually only required if theAPI is extended. Users of predefined sources/sinks/functions do not need to define such hints. Hints withina table program (e.g. field.cast(TIMESTAMP(3).bridgedTo(Timestamp.class))) are ignored.

Planner Compatibility

As mentioned in the introduction, reworking the type system will span multiple releases, and the support of each datatype depends on the used planner. This section aims to summarize the most significant differences.

Old Planner

Flink’s old planner, introduced before Flink 1.9, primarily supports type information. It has only limitedsupport for data types. It is possible to declare data types that can be translated into type information such that theold planner understands them.

The following table summarizes the difference between data type and type information. Most simple types, as well as therow type remain the same. Time types, array types, and the decimal type need special attention. Other hints as the onesmentioned are not allowed.

For the Type Information column the table omits the prefix org.apache.flink.table.api.Types.

For the Data Type Representation column the table omits the prefix org.apache.flink.table.api.DataTypes.

Type InformationJava Expression StringData Type RepresentationRemarks for Data Type
STRING()STRINGSTRING()
BOOLEAN()BOOLEANBOOLEAN()
BYTE()BYTETINYINT()
SHORT()SHORTSMALLINT()
INT()INTINT()
LONG()LONGBIGINT()
FLOAT()FLOATFLOAT()
DOUBLE()DOUBLEDOUBLE()
ROW(…)ROW<…>ROW(…)
BIG_DEC()DECIMAL[DECIMAL()]Not a 1:1 mapping as precision and scale are ignored and Java’s variable precision and scale are used.
SQL_DATE()SQL_DATEDATE().bridgedTo(java.sql.Date.class)
SQL_TIME()SQL_TIMETIME(0).bridgedTo(java.sql.Time.class)
SQL_TIMESTAMP()SQL_TIMESTAMPTIMESTAMP(3).bridgedTo(java.sql.Timestamp.class)
INTERVAL_MONTHS()INTERVAL_MONTHSINTERVAL(MONTH()).bridgedTo(Integer.class)
INTERVAL_MILLIS()INTERVAL_MILLISINTERVAL(DataTypes.SECOND(3)).bridgedTo(Long.class)
PRIMITIVE_ARRAY(…)PRIMITIVE_ARRAY<…>ARRAY(DATATYPE.notNull().bridgedTo(PRIMITIVE.class))Applies to all JVM primitive types except for byte.
PRIMITIVE_ARRAY(BYTE())PRIMITIVE_ARRAY<BYTE>BYTES()
OBJECT_ARRAY(…)OBJECT_ARRAY<…>ARRAY(DATATYPE.bridgedTo(OBJECT.class))
MULTISET(…) MULTISET(…)
MAP(…, …)MAP<…,…>MAP(…)
other generic types ANY(…)

Attention If there is a problem with the new type system. Userscan fallback to type information defined in org.apache.flink.table.api.Types at any time.

The new Blink planner supports all of types of the old planner. This includes in particularthe listed Java expression strings and type information.

The following data types are supported:

Data TypeRemarks for Data Type
STRINGCHAR and VARCHAR are not supported yet.
BOOLEAN
BYTESBINARY and VARBINARY are not supported yet.
DECIMALSupports fixed precision and scale.
TINYINT
SMALLINT
INTEGER
BIGINT
FLOAT
DOUBLE
DATE
TIMESupports only a precision of 0.
TIMESTAMPSupports only a precision of 3.
TIMESTAMP WITH LOCAL TIME ZONESupports only a precision of 3.
INTERVALSupports only interval of MONTH and SECOND(3).
ARRAY
MULTISET
MAP
ROW
ANY

Limitations

Java Expression String: Java expression strings in the Table API such as table.select("field.cast(STRING)")have not been updated to the new type system yet. Use the string representations declared inthe old planner section.

Connector Descriptors and SQL Client: Descriptor string representations have not been updated to the newtype system yet. Use the string representation declared in the Connect to External Systems section

User-defined Functions: User-defined functions cannot declare a data type yet.

List of Data Types

This section lists all pre-defined data types. For the JVM-based Table API those types are also available in org.apache.flink.table.api.DataTypes.

Character Strings

CHAR

Data type of a fixed-length character string.

Declaration

  1. CHAR
  2. CHAR(n)
  1. DataTypes.CHAR(n)

The type can be declared using CHAR(n) where n is the number of code points. n must have a value between 1and 2,147,483,647 (both inclusive). If no length is specified, n is equal to 1.

Bridging to JVM Types

Java TypeInputOutputRemarks
java.lang.StringXXDefault
byte[]XXAssumes UTF-8 encoding.

VARCHAR / STRING

Data type of a variable-length character string.

Declaration

  1. VARCHAR
  2. VARCHAR(n)
  3. STRING
  1. DataTypes.VARCHAR(n)
  2. DataTypes.STRING()

The type can be declared using VARCHAR(n) where n is the maximum number of code points. n must have a valuebetween 1 and 2,147,483,647 (both inclusive). If no length is specified, n is equal to 1.

STRING is a synonym for VARCHAR(2147483647).

Bridging to JVM Types

Java TypeInputOutputRemarks
java.lang.StringXXDefault
byte[]XXAssumes UTF-8 encoding.

Binary Strings

BINARY

Data type of a fixed-length binary string (=a sequence of bytes).

Declaration

  1. BINARY
  2. BINARY(n)
  1. DataTypes.BINARY(n)

The type can be declared using BINARY(n) where n is the number of bytes. n must have a valuebetween 1 and 2,147,483,647 (both inclusive). If no length is specified, n is equal to 1.

Bridging to JVM Types

Java TypeInputOutputRemarks
byte[]XXDefault

VARBINARY / BYTES

Data type of a variable-length binary string (=a sequence of bytes).

Declaration

  1. VARBINARY
  2. VARBINARY(n)
  3. BYTES
  1. DataTypes.VARBINARY(n)
  2. DataTypes.BYTES()

The type can be declared using VARBINARY(n) where n is the maximum number of bytes. n musthave a value between 1 and 2,147,483,647 (both inclusive). If no length is specified, n isequal to 1.

BYTES is a synonym for VARBINARY(2147483647).

Bridging to JVM Types

Java TypeInputOutputRemarks
byte[]XXDefault

Exact Numerics

DECIMAL

Data type of a decimal number with fixed precision and scale.

Declaration

  1. DECIMAL
  2. DECIMAL(p)
  3. DECIMAL(p, s)
  4. DEC
  5. DEC(p)
  6. DEC(p, s)
  7. NUMERIC
  8. NUMERIC(p)
  9. NUMERIC(p, s)
  1. DataTypes.DECIMAL(p, s)

The type can be declared using DECIMAL(p, s) where p is the number of digits in anumber (precision) and s is the number of digits to the right of the decimal pointin a number (scale). p must have a value between 1 and 38 (both inclusive). smust have a value between 0 and p (both inclusive). The default value for p is 10.The default value for s is 0.

NUMERIC(p, s) and DEC(p, s) are synonyms for this type.

Bridging to JVM Types

Java TypeInputOutputRemarks
java.math.BigDecimalXXDefault

TINYINT

Data type of a 1-byte signed integer with values from -128 to 127.

Declaration

  1. TINYINT
  1. DataTypes.TINYINT()

Bridging to JVM Types

Java TypeInputOutputRemarks
java.lang.ByteXXDefault
byteX(X)Output only if type is not nullable.

SMALLINT

Data type of a 2-byte signed integer with values from -32,768 to 32,767.

Declaration

  1. SMALLINT
  1. DataTypes.SMALLINT()

Bridging to JVM Types

Java TypeInputOutputRemarks
java.lang.ShortXXDefault
shortX(X)Output only if type is not nullable.

INT

Data type of a 4-byte signed integer with values from -2,147,483,648 to 2,147,483,647.

Declaration

  1. INT
  2. INTEGER
  1. DataTypes.INT()

INTEGER is a synonym for this type.

Bridging to JVM Types

Java TypeInputOutputRemarks
java.lang.IntegerXXDefault
intX(X)Output only if type is not nullable.

BIGINT

Data type of an 8-byte signed integer with values from -9,223,372,036,854,775,808 to9,223,372,036,854,775,807.

Declaration

  1. BIGINT
  1. DataTypes.BIGINT()

Bridging to JVM Types

Java TypeInputOutputRemarks
java.lang.LongXXDefault
longX(X)Output only if type is not nullable.

Approximate Numerics

FLOAT

Data type of a 4-byte single precision floating point number.

Compared to the SQL standard, the type does not take parameters.

Declaration

  1. FLOAT
  1. DataTypes.FLOAT()

Bridging to JVM Types

Java TypeInputOutputRemarks
java.lang.FloatXXDefault
floatX(X)Output only if type is not nullable.

DOUBLE

Data type of an 8-byte double precision floating point number.

Declaration

  1. DOUBLE
  2. DOUBLE PRECISION
  1. DataTypes.DOUBLE()

DOUBLE PRECISION is a synonym for this type.

Bridging to JVM Types

Java TypeInputOutputRemarks
java.lang.DoubleXXDefault
doubleX(X)Output only if type is not nullable.

Date and Time

DATE

Data type of a date consisting of year-month-day with values ranging from 0000-01-01to 9999-12-31.

Compared to the SQL standard, the range starts at year 0000.

Declaration

  1. DATE
  1. DataTypes.DATE()

Bridging to JVM Types

Java TypeInputOutputRemarks
java.time.LocalDateXXDefault
java.sql.DateXX
java.lang.IntegerXXDescribes the number of days since epoch.
intX(X)Describes the number of days since epoch.Output only if type is not nullable.

TIME

Data type of a time without time zone consisting of hour:minute:second[.fractional] withup to nanosecond precision and values ranging from 00:00:00.000000000 to23:59:59.999999999.

Compared to the SQL standard, leap seconds (23:59:60 and 23:59:61) are not supported asthe semantics are closer to java.time.LocalTime. A time with time zone is not provided.

Declaration

  1. TIME
  2. TIME(p)
  1. DataTypes.TIME(p)

The type can be declared using TIME(p) where p is the number of digits of fractionalseconds (precision). p must have a value between 0 and 9 (both inclusive). If noprecision is specified, p is equal to 0.

Bridging to JVM Types

Java TypeInputOutputRemarks
java.time.LocalTimeXXDefault
java.sql.TimeXX
java.lang.IntegerXXDescribes the number of milliseconds of the day.
intX(X)Describes the number of milliseconds of the day.Output only if type is not nullable.
java.lang.LongXXDescribes the number of nanoseconds of the day.
longX(X)Describes the number of nanoseconds of the day.Output only if type is not nullable.

TIMESTAMP

Data type of a timestamp without time zone consisting of year-month-day hour:minute:second[.fractional]with up to nanosecond precision and values ranging from 0000-01-01 00:00:00.000000000 to9999-12-31 23:59:59.999999999.

Compared to the SQL standard, leap seconds (23:59:60 and 23:59:61) are not supported asthe semantics are closer to java.time.LocalDateTime.

A conversion from and to BIGINT (a JVM long type) is not supported as this would imply a timezone. However, this type is time zone free. For more java.time.Instant-like semantics useTIMESTAMP WITH LOCAL TIME ZONE.

Declaration

  1. TIMESTAMP
  2. TIMESTAMP(p)
  3. TIMESTAMP WITHOUT TIME ZONE
  4. TIMESTAMP(p) WITHOUT TIME ZONE
  1. DataTypes.TIMESTAMP(p)

The type can be declared using TIMESTAMP(p) where p is the number of digits of fractionalseconds (precision). p must have a value between 0 and 9 (both inclusive). If no precisionis specified, p is equal to 6.

TIMESTAMP(p) WITHOUT TIME ZONE is a synonym for this type.

Bridging to JVM Types

Java TypeInputOutputRemarks
java.time.LocalDateTimeXXDefault
java.sql.TimestampXX

TIMESTAMP WITH TIME ZONE

Data type of a timestamp with time zone consisting of year-month-day hour:minute:second[.fractional] zonewith up to nanosecond precision and values ranging from 0000-01-01 00:00:00.000000000 +14:59 to9999-12-31 23:59:59.999999999 -14:59.

Compared to the SQL standard, leap seconds (23:59:60 and 23:59:61) are not supported as the semanticsare closer to java.time.OffsetDateTime.

Compared to TIMESTAMP WITH LOCAL TIME ZONE, the time zone offset information is physicallystored in every datum. It is used individually for every computation, visualization, or communicationto external systems.

Declaration

  1. TIMESTAMP WITH TIME ZONE
  2. TIMESTAMP(p) WITH TIME ZONE
  1. DataTypes.TIMESTAMP_WITH_TIME_ZONE(p)

The type can be declared using TIMESTAMP(p) WITH TIME ZONE where p is the number of digits offractional seconds (precision). p must have a value between 0 and 9 (both inclusive). If noprecision is specified, p is equal to 6.

Bridging to JVM Types

Java TypeInputOutputRemarks
java.time.OffsetDateTimeXXDefault
java.time.ZonedDateTimeX Ignores the zone ID.

TIMESTAMP WITH LOCAL TIME ZONE

Data type of a timestamp with local time zone consisting of year-month-day hour:minute:second[.fractional] zonewith up to nanosecond precision and values ranging from 0000-01-01 00:00:00.000000000 +14:59 to9999-12-31 23:59:59.999999999 -14:59.

Leap seconds (23:59:60 and 23:59:61) are not supported as the semantics are closer to java.time.OffsetDateTime.

Compared to TIMESTAMP WITH TIME ZONE, the time zone offset information is not stored physicallyin every datum. Instead, the type assumes java.time.Instant semantics in UTC time zone atthe edges of the table ecosystem. Every datum is interpreted in the local time zone configured inthe current session for computation and visualization.

This type fills the gap between time zone free and time zone mandatory timestamp types by allowingthe interpretation of UTC timestamps according to the configured session time zone.

Declaration

  1. TIMESTAMP WITH LOCAL TIME ZONE
  2. TIMESTAMP(p) WITH LOCAL TIME ZONE
  1. DataTypes.TIMESTAMP_WITH_LOCAL_TIME_ZONE(p)

The type can be declared using TIMESTAMP(p) WITH LOCAL TIME ZONE where p is the numberof digits of fractional seconds (precision). p must have a value between 0 and 9(both inclusive). If no precision is specified, p is equal to 6.

Bridging to JVM Types

Java TypeInputOutputRemarks
java.time.InstantXXDefault
java.lang.IntegerXXDescribes the number of seconds since epoch.
intX(X)Describes the number of seconds since epoch.Output only if type is not nullable.
java.lang.LongXXDescribes the number of milliseconds since epoch.
longX(X)Describes the number of milliseconds since epoch.Output only if type is not nullable.

INTERVAL YEAR TO MONTH

Data type for a group of year-month interval types.

The type must be parameterized to one of the following resolutions:

  • interval of years,
  • interval of years to months,
  • or interval of months.An interval of year-month consists of +years-months with values ranging from -9999-11 to+9999-11.

The value representation is the same for all types of resolutions. For example, an intervalof months of 50 is always represented in an interval-of-years-to-months format (with defaultyear precision): +04-02.

Declaration

  1. INTERVAL YEAR
  2. INTERVAL YEAR(p)
  3. INTERVAL YEAR(p) TO MONTH
  4. INTERVAL MONTH
  1. DataTypes.INTERVAL(DataTypes.YEAR())
  2. DataTypes.INTERVAL(DataTypes.YEAR(p))
  3. DataTypes.INTERVAL(DataTypes.YEAR(p), DataTypes.MONTH())
  4. DataTypes.INTERVAL(DataTypes.MONTH())

The type can be declared using the above combinations where p is the number of digits of years(year precision). p must have a value between 1 and 4 (both inclusive). If no year precisionis specified, p is equal to 2.

Bridging to JVM Types

Java TypeInputOutputRemarks
java.time.PeriodXXIgnores the days part. Default
java.lang.IntegerXXDescribes the number of months.
intX(X)Describes the number of months.Output only if type is not nullable.

INTERVAL DAY TO MONTH

Data type for a group of day-time interval types.

The type must be parameterized to one of the following resolutions with up to nanosecond precision:

  • interval of days,
  • interval of days to hours,
  • interval of days to minutes,
  • interval of days to seconds,
  • interval of hours,
  • interval of hours to minutes,
  • interval of hours to seconds,
  • interval of minutes,
  • interval of minutes to seconds,
  • or interval of seconds.An interval of day-time consists of +days hours:months:seconds.fractional with values ranging from-999999 23:59:59.999999999 to +999999 23:59:59.999999999. The value representation is the samefor all types of resolutions. For example, an interval of seconds of 70 is always represented inan interval-of-days-to-seconds format (with default precisions): +00 00:01:10.000000.

Declaration

  1. INTERVAL DAY
  2. INTERVAL DAY(p1)
  3. INTERVAL DAY(p1) TO HOUR
  4. INTERVAL DAY(p1) TO MINUTE
  5. INTERVAL DAY(p1) TO SECOND(p2)
  6. INTERVAL HOUR
  7. INTERVAL HOUR TO MINUTE
  8. INTERVAL HOUR TO SECOND(p2)
  9. INTERVAL MINUTE
  10. INTERVAL MINUTE TO SECOND(p2)
  11. INTERVAL SECOND
  12. INTERVAL SECOND(p2)
  1. DataTypes.INTERVAL(DataTypes.DAY())
  2. DataTypes.INTERVAL(DataTypes.DAY(p1))
  3. DataTypes.INTERVAL(DataTypes.DAY(p1), DataTypes.HOUR())
  4. DataTypes.INTERVAL(DataTypes.DAY(p1), DataTypes.MINUTE())
  5. DataTypes.INTERVAL(DataTypes.DAY(p1), DataTypes.SECOND(p2))
  6. DataTypes.INTERVAL(DataTypes.HOUR())
  7. DataTypes.INTERVAL(DataTypes.HOUR(), DataTypes.MINUTE())
  8. DataTypes.INTERVAL(DataTypes.HOUR(), DataTypes.SECOND(p2))
  9. DataTypes.INTERVAL(DataTypes.MINUTE())
  10. DataTypes.INTERVAL(DataTypes.MINUTE(), DataTypes.SECOND(p2))
  11. DataTypes.INTERVAL(DataTypes.SECOND())
  12. DataTypes.INTERVAL(DataTypes.SECOND(p2))

The type can be declared using the above combinations where p1 is the number of digits of days(day precision) and p2 is the number of digits of fractional seconds (fractional precision).p1 must have a value between 1 and 6 (both inclusive). p2 must have a value between 0and 9 (both inclusive). If no p1 is specified, it is equal to 2 by default. If no p2 isspecified, it is equal to 6 by default.

Bridging to JVM Types

Java TypeInputOutputRemarks
java.time.DurationXXDefault
java.lang.LongXXDescribes the number of milliseconds.
longX(X)Describes the number of milliseconds.Output only if type is not nullable.

Constructured Data Types

ARRAY

Data type of an array of elements with same subtype.

Compared to the SQL standard, the maximum cardinality of an array cannot be specified but isfixed at 2,147,483,647. Also, any valid type is supported as a subtype.

Declaration

  1. ARRAY<t>
  2. t ARRAY
  1. DataTypes.ARRAY(t)

The type can be declared using ARRAY<t> where t is the data type of the containedelements.

t ARRAY is a synonym for being closer to the SQL standard. For example, INT ARRAY isequivalent to ARRAY<INT>.

Bridging to JVM Types

Java TypeInputOutputRemarks
t[](X)(X)Depends on the subtype. Default

MULTISET

Data type of a multiset (=bag). Unlike a set, it allows for multiple instances for each of itselements with a common subtype. Each unique value (including NULL) is mapped to some multiplicity.

There is no restriction of element types; it is the responsibility of the user to ensure uniqueness.

Declaration

  1. MULTISET<t>
  2. t MULTISET
  1. DataTypes.MULTISET(t)

The type can be declared using MULTISET<t> where t is the data typeof the contained elements.

t MULTISET is a synonym for being closer to the SQL standard. For example, INT MULTISET isequivalent to MULTISET<INT>.

Bridging to JVM Types

Java TypeInputOutputRemarks
java.util.Map<t, java.lang.Integer>XXAssigns each value to an integer multiplicity. Default

ROW

Data type of a sequence of fields.

A field consists of a field name, field type, and an optional description. The most specific typeof a row of a table is a row type. In this case, each column of the row corresponds to the fieldof the row type that has the same ordinal position as the column.

Compared to the SQL standard, an optional field description simplifies the handling with complexstructures.

A row type is similar to the STRUCT type known from other non-standard-compliant frameworks.

Declaration

  1. ROW<n0 t0, n1 t1, ...>
  2. ROW<n0 t0 'd0', n1 t1 'd1', ...>
  3. ROW(n0 t0, n1 t1, ...>
  4. ROW(n0 t0 'd0', n1 t1 'd1', ...)
  1. DataTypes.ROW(DataTypes.FIELD(n0, t0), DataTypes.FIELD(n1, t1), ...)
  2. DataTypes.ROW(DataTypes.FIELD(n0, t0, d0), DataTypes.FIELD(n1, t1, d1), ...)

The type can be declared using ROW<n0 t0 'd0', n1 t1 'd1', …> where n is the unique name ofa field, t is the logical type of a field, d is the description of a field.

ROW(…) is a synonym for being closer to the SQL standard. For example, ROW(myField INT, myOtherField BOOLEAN) isequivalent to ROW<myField INT, myOtherField BOOLEAN>.

Bridging to JVM Types

Java TypeInputOutputRemarks
org.apache.flink.types.RowXXDefault

Other Data Types

BOOLEAN

Data type of a boolean with a (possibly) three-valued logic of TRUE, FALSE, and UNKNOWN.

Declaration

  1. BOOLEAN
  1. DataTypes.BOOLEAN()

Bridging to JVM Types

Java TypeInputOutputRemarks
java.lang.BooleanXXDefault
booleanX(X)Output only if type is not nullable.

NULL

Data type for representing untyped NULL values.

The null type is an extension to the SQL standard. A null type has no other valueexcept NULL, thus, it can be cast to any nullable type similar to JVM semantics.

This type helps in representing unknown types in API calls that use a NULL literalas well as bridging to formats such as JSON or Avro that define such a type as well.

This type is not very useful in practice and is just mentioned here for completeness.

Declaration

  1. NULL
  1. DataTypes.NULL()

Bridging to JVM Types

Java TypeInputOutputRemarks
java.lang.ObjectXXDefault
any class (X)Any non-primitive type.

ANY

Data type of an arbitrary serialized type. This type is a black box within the table ecosystemand is only deserialized at the edges.

The any type is an extension to the SQL standard.

Declaration

  1. ANY('class', 'snapshot')
  1. DataTypes.ANY(class, serializer)
  2. DataTypes.ANY(typeInfo)

The type can be declared using ANY('class', 'snapshot') where class is the originating class andsnapshot is the serialized TypeSerializerSnapshot in Base64 encoding. Usually, the type string is notdeclared directly but is generated while persisting the type.

In the API, the ANY type can be declared either by directly supplying a Class + TypeSerializer orby passing TypeInformation and let the framework extract Class + TypeSerializer from there.

Bridging to JVM Types

Java TypeInputOutputRemarks
classXXOriginating class or subclasses (for input) or superclasses (for output). Default
byte[] X