This chapter takes you through the different data types in Hive, which are involved in the table creation. All the data types in Hive are classified into four types, given as follows:

• Column Types
• Literals
• Null Values
• Complex Types

Column Types

Column type are used as column data types of Hive. They are as follows:

Integral Types

Integer type data can be specified using integral data types, INT. When the data range exceeds the range of INT, you need to use BIGINT and if the data range is smaller than the INT, you use SMALLINT. TINYINT is smaller than SMALLINT.

The following table depicts various INT data types:

String Types

String type data types can be specified using single quotes (” ”) or double quotes (” “). It contains two data types: VARCHAR and CHAR. Hive follows C-types escape characters.

The following table depicts various CHAR data types:

Timestamp

It supports traditional UNIX timestamp with optional nanosecond precision. It supports java.sql.Timestamp format “YYYY-MM-DD HH:MM:SS.fffffffff” and format “yyyy-mm-dd hh:mm:ss.ffffffffff”.

Dates

DATE values are described in year/month/day format in the form {{YYYY-MM-DD}}.

Decimals

The DECIMAL type in Hive is as same as Big Decimal format of Java. It is used for representing immutable arbitrary precision. The syntax and example is as follows:

DECIMAL(precision, scale)
decimal(10,0)

Union Types

Union is a collection of heterogeneous data types. You can create an instance using create union. The syntax and example is as follows:

UNIONTYPE<int, double, array<string>, struct<a:int,b:string>>

{0:1} 
{1:2.0} 
{2:["three","four"]} 
{3:{"a":5,"b":"five"}} 
{2:["six","seven"]} 
{3:{"a":8,"b":"eight"}} 
{0:9} 
{1:10.0}

Literals

The following literals are used in Hive:

Floating Point Types

Floating point types are nothing but numbers with decimal points. Generally, this type of data is composed of DOUBLE data type.

Decimal Type

Decimal type data is nothing but floating point value with higher range than DOUBLE data type. The range of decimal type is approximately -10^-308 to 10³⁰⁸.

Null Value

Missing values are represented by the special value NULL.

Complex Types

The Hive complex data types are as follows:

Arrays

Arrays in Hive are used the same way they are used in Java.

Syntax: ARRAY<data_type>

Maps

Maps in Hive are similar to Java Maps.

Syntax: MAP<primitive_type, data_type>

Structs

Structs in Hive is similar to using complex data with comment.

Syntax: STRUCT<col_name : data_type [COMMENT col_comment], ...>