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mongodb/shell/query.js
2010-02-16 11:37:47 -05:00

247 lines
5.6 KiB
JavaScript

// query.js
if ( typeof DBQuery == "undefined" ){
DBQuery = function( mongo , db , collection , ns , query , fields , limit , skip ){
this._mongo = mongo; // 0
this._db = db; // 1
this._collection = collection; // 2
this._ns = ns; // 3
this._query = query || {}; // 4
this._fields = fields; // 5
this._limit = limit || 0; // 6
this._skip = skip || 0; // 7
this._cursor = null;
this._numReturned = 0;
this._special = false;
}
print( "DBQuery probably won't have array access " );
}
DBQuery.prototype.help = function(){
print( "DBQuery help" );
print( "\t.sort( {...} )" )
print( "\t.limit( n )" )
print( "\t.skip( n )" )
print( "\t.count() - total # of objects matching query, ignores skip,limit" )
print( "\t.size() - total # of objects cursor would return skip,limit effect this" )
print( "\t.explain()" )
print( "\t.forEach( func )" )
print( "\t.map( func )" )
}
DBQuery.prototype.clone = function(){
var q = new DBQuery( this._mongo , this._db , this._collection , this._ns ,
this._query , this._fields ,
this._limit , this._skip );
q._special = this._special;
return q;
}
DBQuery.prototype._ensureSpecial = function(){
if ( this._special )
return;
var n = { query : this._query };
this._query = n;
this._special = true;
}
DBQuery.prototype._checkModify = function(){
if ( this._cursor )
throw "query already executed";
}
DBQuery.prototype._exec = function(){
if ( ! this._cursor ){
assert.eq( 0 , this._numReturned );
this._cursor = this._mongo.find( this._ns , this._query , this._fields , this._limit , this._skip );
this._cursorSeen = 0;
}
return this._cursor;
}
DBQuery.prototype.limit = function( limit ){
this._checkModify();
this._limit = limit;
return this;
}
DBQuery.prototype.skip = function( skip ){
this._checkModify();
this._skip = skip;
return this;
}
DBQuery.prototype.hasNext = function(){
this._exec();
if ( this._limit > 0 && this._cursorSeen >= this._limit )
return false;
var o = this._cursor.hasNext();
return o;
}
DBQuery.prototype.next = function(){
this._exec();
var o = this._cursor.hasNext();
if ( o )
this._cursorSeen++;
else
throw "error hasNext: " + o;
var ret = this._cursor.next();
if ( ret.$err && this._numReturned == 0 && ! this.hasNext() )
throw "error: " + tojson( ret );
this._numReturned++;
return ret;
}
DBQuery.prototype.toArray = function(){
if ( this._arr )
return this._arr;
var a = [];
while ( this.hasNext() )
a.push( this.next() );
this._arr = a;
return a;
}
DBQuery.prototype.count = function( applySkipLimit ){
var cmd = { count: this._collection.getName() };
if ( this._query ){
if ( this._special )
cmd.query = this._query.query;
else
cmd.query = this._query;
}
cmd.fields = this._fields || {};
if ( applySkipLimit ){
if ( this._limit )
cmd.limit = this._limit;
if ( this._skip )
cmd.skip = this._skip;
}
var res = this._db.runCommand( cmd );
if( res && res.n != null ) return res.n;
throw "count failed: " + tojson( res );
}
DBQuery.prototype.size = function(){
return this.count( true );
}
DBQuery.prototype.countReturn = function(){
var c = this.count();
if ( this._skip )
c = c - this._skip;
if ( this._limit > 0 && this._limit < c )
return this._limit;
return c;
}
/**
* iterative count - only for testing
*/
DBQuery.prototype.itcount = function(){
var num = 0;
while ( this.hasNext() ){
num++;
this.next();
}
return num;
}
DBQuery.prototype.length = function(){
return this.toArray().length;
}
DBQuery.prototype._addSpecial = function( name , value ){
this._ensureSpecial();
this._query[name] = value;
return this;
}
DBQuery.prototype.sort = function( sortBy ){
return this._addSpecial( "orderby" , sortBy );
}
DBQuery.prototype.hint = function( hint ){
return this._addSpecial( "$hint" , hint );
}
DBQuery.prototype.min = function( min ) {
return this._addSpecial( "$min" , min );
}
DBQuery.prototype.max = function( max ) {
return this._addSpecial( "$max" , max );
}
DBQuery.prototype.forEach = function( func ){
while ( this.hasNext() )
func( this.next() );
}
DBQuery.prototype.map = function( func ){
var a = [];
while ( this.hasNext() )
a.push( func( this.next() ) );
return a;
}
DBQuery.prototype.arrayAccess = function( idx ){
return this.toArray()[idx];
}
DBQuery.prototype.explain = function(){
var n = this.clone();
n._ensureSpecial();
n._query.$explain = true;
n._limit = n._limit * -1;
return n.next();
}
DBQuery.prototype.snapshot = function(){
this._ensureSpecial();
this._query.$snapshot = true;
return this;
}
DBQuery.prototype.shellPrint = function(){
try {
var n = 0;
while ( this.hasNext() && n < 20 ){
var s = tojson( this.next() , "" , true );
print( s );
n++;
}
if ( this.hasNext() ){
print( "has more" );
___it___ = this;
}
else {
___it___ = null;
}
}
catch ( e ){
print( e );
}
}
DBQuery.prototype.toString = function(){
return "DBQuery: " + this._ns + " -> " + tojson( this.query );
}