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arangodb/js/server/modules/simple-query.js

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JavaScript

////////////////////////////////////////////////////////////////////////////////
/// @brief Arango Simple Query Language
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2012 triagens GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
/// http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is triAGENS GmbH, Cologne, Germany
///
/// @author Dr. Frank Celler
/// @author Copyright 2012, triAGENS GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////
var internal = require("internal");
var console = require("console");
var SQ = require("simple-query-basics");
// -----------------------------------------------------------------------------
// --SECTION-- SIMPLE QUERY ALL
// -----------------------------------------------------------------------------
// -----------------------------------------------------------------------------
// --SECTION-- private functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @addtogroup SimpleQuery
/// @{
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
/// @brief executes an all query
////////////////////////////////////////////////////////////////////////////////
SQ.SimpleQueryAll.prototype.execute = function () {
var documents;
if (this._execution === null) {
if (this._skip === null) {
this._skip = 0;
}
documents = this._collection.ALL(this._skip, this._limit);
this._execution = new SQ.GeneralArrayCursor(documents.documents);
this._countQuery = documents.count;
this._countTotal = documents.total;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////
// -----------------------------------------------------------------------------
// --SECTION-- QUERY BY EXAMPLE
// -----------------------------------------------------------------------------
// -----------------------------------------------------------------------------
// --SECTION-- private functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @addtogroup SimpleQuery
/// @{
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
/// @brief query-by scan or hash index
////////////////////////////////////////////////////////////////////////////////
function ByExample (collection, example, skip, limit) {
var unique = true;
var documentId = null;
var attributes = [];
for (var k in example) {
if (example.hasOwnProperty(k)) {
attributes.push(k);
if (example[k] === null) {
unique = false;
}
else if (k === '_id') {
// example contains the document id in attribute "_id"
documentId = example[k];
break;
}
}
}
if (documentId !== null) {
// we can use the collection's primary index
var doc;
try {
// look up document by id
doc = collection.document(documentId);
}
catch (e) {
}
return { "total" : doc ? 1 : 0, "count" : doc ? 1 : 0, "documents" : doc ? [ doc ] : [ ] };
}
var idx = collection.lookupHashIndex.apply(collection, attributes);
if (idx === null && unique) {
idx = collection.lookupUniqueConstraint.apply(collection, attributes);
if (idx !== null) {
console.debug("found unique constraint %s", idx.id);
}
}
else {
console.debug("found hash index %s", idx.id);
}
if (idx !== null) {
// use hash index
return collection.BY_EXAMPLE_HASH(idx.id, example, skip, limit);
}
else {
// use full collection scan
return collection.BY_EXAMPLE(example, skip, limit);
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief executes a query-by-example
////////////////////////////////////////////////////////////////////////////////
SQ.SimpleQueryByExample.prototype.execute = function () {
var documents;
if (this._execution === null) {
if (this._skip === null || this._skip <= 0) {
this._skip = 0;
}
var documents = ByExample(this._collection, this._example, this._skip, this._limit);
this._execution = new SQ.GeneralArrayCursor(documents.documents);
this._countQuery = documents.count;
this._countTotal = documents.total;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////
// -----------------------------------------------------------------------------
// --SECTION-- public functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @addtogroup SimpleQuery
/// @{
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
/// @brief constructs a query-by-example for a collection
///
/// @FUN{@FA{collection}.firstExample(@FA{example})}
///
/// Returns the a document of a collection that match the specified example or
/// @LIT{null}. The example must be specified as paths and values. See
/// @FN{byExample} for details.
///
/// @FUN{@FA{collection}.firstExample(@FA{path1}, @FA{value1}, ...)}
///
/// As alternative you can supply a list of paths and values.
///
/// @EXAMPLES
///
/// @TINYEXAMPLE{shell-simple-query-first-example,finds a document with a given name}
////////////////////////////////////////////////////////////////////////////////
ArangoCollection.prototype.firstExample = function () {
var example;
// example is given as only argument
if (arguments.length === 1) {
example = arguments[0];
}
// example is given as list
else {
example = {};
for (var i = 0; i < arguments.length; i += 2) {
example[arguments[i]] = arguments[i + 1];
}
}
var documents = ByExample(this, example, 0, 1);
if (0 < documents.documents.length) {
return documents.documents[0];
}
else {
return null;
}
}
ArangoEdgesCollection.prototype.firstExample = ArangoCollection.prototype.firstExample;
////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////
// -----------------------------------------------------------------------------
// --SECTION-- RANGED QUERY
// -----------------------------------------------------------------------------
// -----------------------------------------------------------------------------
// --SECTION-- private functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @addtogroup SimpleQuery
/// @{
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
/// @brief ranged query
////////////////////////////////////////////////////////////////////////////////
function RangedQuery (collection, attribute, left, right, type, skip, limit) {
var idx = collection.lookupSkiplist(attribute);
if (idx === null) {
idx = collection.lookupUniqueSkiplist(attribute);
if (idx !== null) {
console.debug("found unique skip-list index %s", idx.id);
}
}
else {
console.debug("found skip-list index %s", idx.id);
}
if (idx !== null) {
var cond = {};
if (type === 0) {
cond[attribute] = [ [ ">=", left ], [ "<", right ] ];
}
else if (type === 1) {
cond[attribute] = [ [ ">=", left ], [ "<=", right ] ];
}
else {
throw "unknown type";
}
return collection.BY_CONDITION_SKIPLIST(idx.id, cond, skip, limit);
}
else {
throw "not implemented";
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief executes a query-by-example
////////////////////////////////////////////////////////////////////////////////
SQ.SimpleQueryRange.prototype.execute = function () {
var documents;
if (this._execution === null) {
if (this._skip === null) {
this._skip = 0;
}
var documents = RangedQuery(this._collection,
this._attribute,
this._left,
this._right,
this._type,
this._skip,
this._limit);
this._execution = new SQ.GeneralArrayCursor(documents.documents);
this._countQuery = documents.count;
this._countTotal = documents.total;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////
// -----------------------------------------------------------------------------
// --SECTION-- SIMPLE QUERY NEAR
// -----------------------------------------------------------------------------
// -----------------------------------------------------------------------------
// --SECTION-- private functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @addtogroup SimpleQuery
/// @{
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
/// @brief executes an all query
////////////////////////////////////////////////////////////////////////////////
SQ.SimpleQueryNear.prototype.execute = function () {
var result;
var documents;
var distances;
var limit;
if (this._execution === null) {
if (this._skip === null) {
this._skip = 0;
}
if (this._skip < 0) {
var err = new ArangoError();
err.errorNum = internal.errors.ERROR_BAD_PARAMETER;
err.errorMessage = "skip must be non-negative";
throw err;
}
if (this._limit === null) {
limit = this._skip + 100;
}
else {
limit = this._skip + this._limit;
}
result = this._collection.NEAR(this._index, this._latitude, this._longitude, limit);
documents = result.documents;
distances = result.distances;
if (this._distance !== null) {
for (var i = this._skip; i < documents.length; ++i) {
documents[i][this._distance] = distances[i];
}
}
this._execution = new SQ.GeneralArrayCursor(result.documents, this._skip, null);
this._countQuery = result.documents.length - this._skip;
this._countTotal = result.documents.length;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////
// -----------------------------------------------------------------------------
// --SECTION-- SIMPLE QUERY WITHIN
// -----------------------------------------------------------------------------
// -----------------------------------------------------------------------------
// --SECTION-- private functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @addtogroup SimpleQuery
/// @{
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
/// @brief executes an all query
////////////////////////////////////////////////////////////////////////////////
SQ.SimpleQueryWithin.prototype.execute = function () {
var result;
var documents;
var distances;
var limit;
if (this._execution === null) {
result = this._collection.WITHIN(this._index, this._latitude, this._longitude, this._radius);
documents = result.documents;
distances = result.distances;
if (this._distance !== null) {
for (var i = this._skip; i < documents.length; ++i) {
documents[i][this._distance] = distances[i];
}
}
this._execution = new SQ.GeneralArrayCursor(result.documents, this._skip, this._limit);
this._countQuery = result.documents.length - this._skip;
this._countTotal = result.documents.length;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////
// -----------------------------------------------------------------------------
// --SECTION-- MODULE EXPORTS
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @addtogroup SimpleQuery
/// @{
////////////////////////////////////////////////////////////////////////////////
exports.SimpleQueryAll = SQ.SimpleQueryAll;
exports.SimpleQueryByExample = SQ.SimpleQueryByExample;
exports.SimpleQueryGeo = SQ.SimpleQueryGeo;
exports.SimpleQueryNear = SQ.SimpleQueryNear;
exports.SimpleQueryWithin = SQ.SimpleQueryWithin;
////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////
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