Databases Reference
In-Depth Information
import com.mongodb.Mongo;
import com.mongodb.DB;
import com.mongodb.DBCollection;
class ChemSearch {
public static void main(String[] args) {
Mongo connection = new Mongo();
DB db = connection.getDB("search");
DBCollection chemicals = db.getCollection("chemicals");
/* ... */
}
}
This will connect to
localhost:27017
and get the
search.chemicals
namespace.
Documents in Java must be instances of
org.bson.DBObject
, an interface that is basically
an ordered
java.util.Map
. While there are a few ways to create a document in Java, the
simplest one is to use the
com.mongodb.BasicDBObject
class. Thus, creating the docu-
ment that could be represented by the shell as
{"x" : 1, "y" : "foo"}
would look like
this:
BasicDBObject doc = new BasicDBObject();
doc.put("x", 1);
doc.put("y", "foo");
If we wanted to add an embedded document, such as
"z" : {"hello" : "world"}
, we
would create another BasicDBObject and then
put
it in the top-level one:
BasicDBObject z = new BasicDBObject();
z.put("hello", "world");
doc.put("z", z);
Then we would have the document
{"x" : 1, "y" : "foo", "z" : {"hello" :
"world"}}
.
From there, all of the other methods implemented by the Java driver are similar to the
shell. For instance, we could say
chemicals.insert(doc)
or
chemicals.find(doc)
. There
is full API documentation for the Java driver at
http://api.mongodb.org/java
and some
articles on specific areas of interest (concurrency, data types, etc.) at the
MongoDB Java
Schema Design
The interesting thing about this problem is that there are thousands of possible prop-
erties for each chemical, and we want to be able to search for any of them efficiently.
Take two simple examples: silicon and silicon nitride. A document representing silicon
might look something like this:
{
"name" : "silicon",
