Hadoop Interview Questions And Answers Part-2 | Big Data Interview Questions & Answers | Simplilearn
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The document outlines various commands and configurations for managing databases using Hadoop frameworks like Hive, HBase, and Sqoop. It includes examples of creating tables, loading and exporting data, altering table schemas, and executing SQL queries. Additionally, it provides commands specific to HBase for enabling, disabling, and modifying tables, as well as interacting with MySQL databases using Sqoop.
Hadoop Interview Questions And Answers Part-2 | Big Data Interview Questions & Answers | Simplilearn
- 4. • • • •
- 9. CREATE TABLE test (registration_no INT, name STRING, email STRING, address STRING) ROW FORMAT FIELDS DELIMITED TERMINATED BY ‘,’ STORED AS TEXTFILE; LOAD DATA INPATH ‘/user/input’ INTO TABLE test; CREATE TABLE test_seqfile (registration_no INT, name STRING, email STRING, address STRING) ROW FORMAT FIELDS DELIMITED TERMINATED BY ‘,’ STORED AS SEQUENCEFILE; INSERT OVERWRITE TABLE test_seqfile SELECT * FROM test;
- 10. ALTER TABLE h_table CHANGE COLUMN new_col INT BEFORE x_col
- 17. • • • • • • • •
- 18. Group_data = GROUP Relation_name BY AGE Relation_2 = ORDER Relation_name1 BY (ASC|DSC) Relation_2 = DISTINCT Relation_name1
- 20. Example:
- 21. test_data = LOAD “/user/test.txt” USING PigStorage(‘,’) as (field1, field2,….); Limit_test_data = LIMIT test_data 10;
- 23. ….
- 24. …. • •
- 25. ….
- 28. Configuration myConf = HBaseConfiguration.create(); HTableInterface usersTable = new HTable(myConf, “users”);
- 29. disable ‘hbase1’ alter ‘hbase1’, {NAME => ‘family_name’, REPLICATION_SCOPE => ‘1’} enable ‘hbase1’
- 30. hbase org.apache.hadoop.hbase.mapreduce.Export “table name” “target export location” create ‘emp_table_import’, {NAME => ‘myfam’, VERSIONS => 10} hbase org.apache.hadoop.hbase.mapreduce.Import “table name” “target import location” hbase org.apache.hadoop.hbase.mapreduce.Export “employee_table” “/export/employee_table” create ‘emp_table_import’, {NAME => ‘myfam’, VERSIONS => 10} hbase org.apache.hadoop.hbase.mapreduce.Import “emp_table_import” “/export/employee_table”
- 34. • • • •
- 35. scan ‘table_name’ Example: scan ‘employee_table’ alter ‘table_name’, ‘column_family_name’ Example: alter ‘employee_table’, ‘emp_address’
- 36. • • •
- 37. • •
- 40. • • • • • •
- 41. Example: sqoop eval --connect jdbc:mysql://localhost/employee --username root --password cloudera --query “select * from employee_table” sqoop eval --connect jdbc:mysql://localhost/db --username root -- password cloudera --query “sql statement”
- 44. Example: sqoop import --connect jdbc:mysql://quickstart.cloudera/test_db -- username root –-password cloudera --table test_demo Syntax: sqoop import --connect jdbc:mysql://localhost/db --username root –-password cloudera --table table_name
- 45. create table dept(department_id int not null default NULL auto_increment, department_name varchar(45) not null default 'NULL', primary key(department_id)); sqoop export --connect jdbc:mysql://localhost/retail_db –username root --password cloudera --table dept –- export-dir /user/cloudera/departments
- 46. • • • • •
- 47. --update-key parameter sqoop export --connect jdbc:mysql://localhost/dbname –username root –password cloudera --export-dir /input/dir --table test_demo –-fields-terminated-by “,” --update-key column_name