Database Reference
In-Depth Information
CREATE EXTERNAL TABLE packtPubEmployee (item map<string,
string>)
STORED BY
'org.apache.hadoop.hive.dynamodb.DynamoDBStorageHandler'
TBLPROPERTIES ("dynamodb.table.name" = "Employee");
INSERT OVERWRITE TABLE packtPubEmployee SELECT * FROM
packtPubEmployee_s3;
Here, instead of specifying attributes in the table, we are giving a single-map variable that
would store all the values, and which would add the data to corresponding attributes. But
as we don't have any attributes specified, we cannot query such tables in Hive as we
would not have attribute names with us.
Importing data from HDFS
We saw data export to HDFS from DynamoDB; in the same manner, you can import data
to DynamoDB from HDFS flat files. Here, first we need to create a table in hive that is
linked to a directory on HDFS. Then, we need to create another table that links to a table
in DynamoDB where you need to put the data. Now, you can simply insert data from the
first to the second table, and you would be able to see the data imported in the Dy-
namoDB table.
In the following example, we would try to import the data present on the HDFS path
/data/employee
to the
Employee
table in DynamoDB:
CREATE EXTERNAL TABLE packtPubEmployee_hdfs(empid String,
yoj String, department String, salary bigint, ,manager
String)
ROW FORMAT DELIMITED FIELDS TERMINATED BY ','
LOCATION 'hdfs:///data/employee/';
CREATE EXTERNAL TABLE packtPubEmployee (empid String, yoj
String, department String, salary bigint, manager String)
STORED BY
'org.apache.hadoop.hive.dynamodb.DynamoDBStorageHandler'
TBLPROPERTIES ("dynamodb.table.name" = "Employee",
"dynamodb.column.mapping" =
"empid:empId,yoj:yoj,department:dept,salary:salary,manager:manager");
