Hive Complex Data Types with Examples

In this post, I am going to explain an example that cover following data types in Hive.

 

a.   Array

b.   Map

c.    Struct

 

Array: Represent an ordered collection of elements. Elements in the array must be of same type and dynamic in size.

 

Example: hobbies ARRAY<STRING>

 

Map: It is a collection of <key, value> pairs.

 

Struct: It is similar to a structure in C, class in Java. Struct is a collection of different data types.

 

Example

CREATE TABLE emp (
id INT,
name STRING,
hobbies ARRAY<STRING>,
experience MAP<STRING,STRING>,
gender_age STRUCT<gender:STRING,age:INT>
)
ROW FORMAT DELIMITED
FIELDS TERMINATED BY '|'
COLLECTION ITEMS TERMINATED BY ','
MAP KEYS TERMINATED BY ':'
STORED AS TEXTFILE;

 

In the above example,

a.   ‘hobbies’ is of type array

b.   ‘experience’ is of type map

c.    ‘gender_age’ is of type struct.

 

Let’s experiment with the above example.

 

Step 1: Create emp table.

hive> CREATE TABLE emp (
    > id INT,
    > name STRING,
    > hobbies ARRAY<STRING>,
    > technology_experience MAP<STRING,STRING>,
    > gender_age STRUCT<gender:STRING,age:INT>
    > )
    > ROW FORMAT DELIMITED
    > FIELDS TERMINATED BY '|'
    > COLLECTION ITEMS TERMINATED BY ','
    > MAP KEYS TERMINATED BY ':'
    > STORED AS TEXTFILE;
OK
Time taken: 0.045 seconds
hive> ;
hive> ;
hive> DESC emp;
OK
id                    int                                       
name                  string                                    
hobbies               array<string>                             
technology_experience map<string,string>                        
gender_age            struct<gender:string,age:int>                     
Time taken: 0.082 seconds, Fetched: 5 row(s)

 

Step 2: Create empInfo.txt file with below content.

 

empInfo.txt

 

1|Hari|Football,Cricket|Java:3.4Yrs,C:4.5Yrs|Male,30
2|Chamu|Trekking,Watching movies|Selenium:5.6Yrs|Feale,38
3|Sailu|Chess,Listening to music|EmbeddedC:9Yrs|Femle,32
4|Gopi|Cricket|Datastage:11Yrs|Male,32

 

Step 3: load empInfo.txt file content to emp table.

LOAD DATA LOCAL INPATH '/home/cloudera/examples/hive/empInfo.txt' into table emp;

 

hive> LOAD DATA LOCAL INPATH '/home/cloudera/examples/hive/empInfo.txt' into table emp;
Loading data to table default.emp
Table default.emp stats: [numFiles=1, totalSize=207]
OK
Time taken: 0.619 seconds

 

Print all the records from emp table.

hive> SELECT * FROM emp;
OK
1   Hari    ["Football","Cricket"]  {"Java":"3.4Yrs","C":"4.5Yrs"}  {"gender":"Male","age":30}
2   Chamu   ["Trekking","Watching movies"]  {"Selenium":"5.6Yrs"}   {"gender":"Feale","age":38}
3   Sailu   ["Chess","Listening to music"]  {"EmbeddedC":"9Yrs"}    {"gender":"Femle","age":32}
4   Gopi    ["Cricket"] {"Datastage":"11Yrs"}   {"gender":"Male","age":32}
Time taken: 0.293 seconds, Fetched: 4 row(s)

 

 

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