Creating JSON Tables
This topic describes how to create HPE Ezmeral Data Fabric Database JSON tables using either programmatic APIs or dbshell.
sample
, the command would
be:// Create directories with hadoop
hadoop fs -mkdir /sample
// Create a Data Fabric volume using maprcli create volume
maprcli volume create -name sample -path /sample -type rw
The following Java code examples show you how to create a table in the following ways:
- By using the default values for the table attributes,
- By setting specific values for the table attributes.
See the Admin and TableDescriptor APIs for more information.
The following example shows how to create a table by calling an
Admin
object's createTable() method
and
passing, as an argument, the path that you want to use for the new table:
public void createJSONTable(String tablePath) throws DBException {
try (Admin admin = MapRDB.newAdmin()) {
if (!admin.tableExists(tablePath)) {
admin.createTable(tablePath);
}
}
}
Tables created with this version of the createTable()
method use
the default values for their attributes.
Alternatively, the following example how to create a table by passing a
TableDescriptor
object as an argument to the
createTable() method
:
/* Create a TableDescriptor for the table to create,
* passing in the path of the table.
*/
TableDescriptor tableDescriptor = MapRDB.newTableDescriptor(tablePath);
/* Pass the TableDescriptor object and the path to the table
* to the Admin.createTable() method.
*/
public void createJSONTable(String tablePath, TableDescriptor tableDescriptor) throws DBException {
try (Admin admin = MapRDB.newAdmin()) {
if (!admin.tableExists(tablePath)) {
admin.createTable(tableDescriptor);
}
}
}
This alternative allows you to set values for some of the table's attributes.
To create a table in the Node.js OJAI client, call the
Connection.createStore()
method:
connection.createStore(table_path)
.then((store) => {
// Process result
...
});
The method returns a DocumentStore
object.
To create a table in the Python OJAI client, call the
Connection.create_store()
method:
store = connection.create_store(store_path=table_path)
The method returns a DocumentStore
object.
The following dbshell command shows code syntax for creating a table:
# mapr dbshell
maprdb root:> create /<tablePath>/<tableName>
To create a table in the C# OJAI client, call the
connection.CreateStore(string storePath)
method:
var store = connection.CreateStore(string storePath);
The method returns a DocumentStore
object.
To create a table in the Go OJAI client, call the
connection.CreateStore()
function:
store, error := connection.CreateStore("/store_path")
The function returns a new DocumentStore
and an error.