What is co Group in pig?

Advertisements. The COGROUP operator works more or less in the same way as the GROUP operator. The only difference between the two operators is that the group operator is normally used with one relation, while the cogroup operator is used in statements involving two or more relations.

What is relation in pig?

Pig Latin statements work with relations. A relation can be defined as follows: A relation is a bag (more specifically, an outer bag). A bag is a collection of tuples. A tuple is an ordered set of fields.

How do pigs create relationships?

Now, you can use ‘C’ as the ’empty relation’ that has one empty tuple. DEFINE GenerateRelationFromString(string) RETURNS relation { temp = LOAD ‘somefile’; tempLimit1 = LIMIT temp 1; $relation = FOREACH tempLimit1 GENERATE FLATTEN(TOKENIZE(‘$string’, ‘,’)); };

How do you define the schema of a pig?

Schema assigns name to the field and declares data type of the field. It is optional in pig but it is recommended to use them for getting good results. We have seen in the load function that we have defined datatypes for every field, using describe command we can see the schema.

What is flatten in pig?

The FLATTEN operator looks like a UDF syntactically, but it is actually an operator that changes the structure of tuples and bags in a way that a UDF cannot. Flatten un-nests tuples as well as bags. The idea is the same, but the operation and result is different for each type of structure. 2 Kudos.

How do you split a pig?

The Apache Pig SPLIT operator breaks the relation into two or more relations according to the provided expression. Here, a tuple may or may not be assigned to one or more than one relation.

What is pig UDF?

Pig provides extensive support for user defined functions (UDFs) as a way to specify custom processing. The most extensive support is provided for Java functions. You can customize all parts of the processing including data load/store, column transformation, and aggregation.

What is describe in pig?

Advertisements. The describe operator is used to view the schema of a relation.

What are the relational operators available related to grouping and joining in Pig language?

Q46 What are the relational operators available related to combining and splitting in pig language? Answer: UNION and SPLIT used for combining and splitting relations in the pig.

How can you integrate the data of two relations using Pig?

Syntax. Here is how you can perform a JOIN operation on two tables using multiple keys. grunt> Relation3_name = JOIN Relation2_name BY (key1, key2), Relation3_name BY (key1, key2);

How do you group a pig?

The Apache Pig GROUP operator is used to group the data in one or more relations. It groups the tuples that contain a similar group key. If the group key has more than one field, it treats as tuple otherwise it will be the same type as that of the group key.

How do I exit grunt shell?

quit – Quit the grunt shell.

What is CoGroup in Apache Pig?

Apache Pig – Cogroup Operator. The COGROUP operator works more or less in the same way as the GROUP operator. The only difference between the two operators is that the group operator is normally used with one relation, while the cogroup operator is used in statements involving two or more relations.

What is a pig?

A pig is any of the animals in the genus Sus, within the even-toed ungulate family Suidae. Pigs include domestic pigs and their ancestor, the common Eurasian wild boar ( Sus scrofa ), along with other species. Pigs, like all suids, are native to the Eurasian and African continents, ranging from Europe to the Pacific islands.

How intelligent is a pet pig?

Pigs are highly intelligent animals, on par with dogs, and according to David DiSalvo’s writing in Forbes, they are “widely considered the smartest domesticated animal in the world.

What is the ancestor of the domestic pig?

The ancestor of the domestic pig is the wild boar, which is one of the most numerous and widespread large mammals. Its many subspecies are native to all but the harshest climates of continental Eurasia and its islands and Africa as well, from Ireland and India to Japan and north to Siberia.