Instructions for using updateapi interface of MongoDB database

From two aspects to explain. Shell command line description, java client API description;

java client example:

set = conn.prepareStatement(querysql+fromsql).executeQuery()
;

while(set. next()){

DBObject q = new BasicDBObject().append(“T”, “a”)

.append(“CI”, String. valueOf(set. getInt(1)))

.append(“AI”, String.valueOf(set.getInt(3)));

DBObject o = new BasicDBObject().append(“$set”,

new BasicDBObject().append(“CN”, set.getString(2))

.append(“AN”, set.getString(4)).append(“S”,
set. getString(5)));

Mongodb.getDB(“yqflog”).getCollection(“info”).update(q, o, true
, true );

}

mongodb java client api:

/**

* calls {@link
DBCollection#update(com.mongodb.DBObject, com.mongodb.DBObject,
boolean, boolean, com.mongodb.WriteConcern)} with default
Write Concern.

* @param q search query for old object to
update

* @param o object with which to update
q

* @param upsert if the database should
create the element if it does not exist

* @param multi if the update should be
applied to all objects matching (db version 1.1.3 and above)

* * *
See http://www.mongodb.org/display/DOCS/Atomic+Operations

* @return

* @throws MongoException

* @dochub update

*/

public WriteResult update( DBObject q , DBObject o
, boolean upsert , boolean multi )

  throws MongoException {

return update( q , o , upsert ,
multi , getWriteConcern() );

}

shell command line:

db.collection.update( criteria, objNew, upsert, multi )

Arguments:

criteria – query which selects the record
to update;

objNew – updated object or $ operators
(e.g., $inc) which manipulate the object

upsert – if this should be an “upsert”
operation; that is, if the record(s) do not exist, insert
one. Upsert only inserts a single document.

multi – indicates if all documents
matching criteria should be updated
rather than just one. Can be useful with the $ operators below.

$options operation instructions:

$set is used in the example, otherwise the original value will be lost;

$inc
{ $inc : { field : value } }

increments field by the
number value if field is
present in the object, otherwise
sets field to the
number value. This can also be used to
decrement by using a negative value.

$set
{ $set : { field : value } }

sets field to value.
All datatypes are supported with $set.

$unset
{ $unset : { field : 1} }

Deletes a given field. v1.3+