Today I'm going to publish the blogpost , which has been writtenby Javier De La Torre Medina . Thanks to him for the great research!All below is his article.
Oracle Big Data SQL over complex data types in Oracle NoSQLWhen working with Oracle NoSQL databases, we have the flexibility to choose complex data types like arrays, records and map. In this example we are going to show you how to use Oracle Big Data SQL over these complex data types.
Let’s use one Oracle NoSQL table included with the virtual machine Oracle Big Data Lite. This table it’s called: movie. This table includes simple data types like: string, integer, etc. but the last column is an array data type. On the Oracle NoSQL database, we can see the description of the table. We are going to focus only on the array:
kv-> show table -name movie
…….
{
"name" : "genres",
"type" : "ARRAY",
"collection" : {
"name" : "RECORD_gen",
"type" : "RECORD",
"fields" : [ {"name" : "cid",
"type" : "STRING",
"nullable" : true,
"default" : null
}, {
"name" : "id",
"type" : "INTEGER",
"nullable" : true,
"default" : null
}, {
"name" : "name",
"type" : "STRING",
"nullable" : true,
"default" : null
} ]
},
Let’s have a look into the data.
kv-> get table -name movie
We can see the array as the last column. Let’s create a Hive table on top of the Oracle NoSQL table.
Now we can run a simple query to see if works:
And also we can query the array directly:
Now we can create the Oracle Big Data SQL table on top. On the following documentation link, we can see how is the mapping between different data types are done: http://docs.oracle.com/cd/NOSQL/html/examples/hadoop/hive/table/package-summary.html#ondb_hive_ora_data_model_mapping_table
We will have to create the table as varchar2 data type and we will define that GENRE column is an array. Here is the code to create the table:
Now let’s run some queries. Let’s run a simple one, let’s query two columns to see how the data looks like:
Let’s query over the GENRES column. In this case we will use the JSON_QUERY operator. This operator always returns a JSON, like an object or an array. Oracle Database 12c can work natively with JSON, so we will be able to query and select the field we want. As a final example, let’s query over the name field:
