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Why in Mongo Timestamp 2 dates?

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Saumya last edited by

increment there for what? What's that? http://php.net/manual/en/mongodb-bson-timestamp.construct.php
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Bogopo last edited by

https://docs.mongodb.com/manual/reference/bson-types/#timestamps
The BSON timestamp type is for internal MongoDB use. For most cases, in application development, you will want to use the BSON date type.
This type of data is intended for internal use mongodb and should not normally be used outside.
As it says, within one instant mongod field timestamp Must always be unique. increment - A different number with little meaning to create unique identifiers within one second of the unix era.
I repeat, this type of data doesn't have to be used. Use the type. Date instead of him. Moreover, in contrast to timestamp, Date 64-bit and not prone to the 2038 problem, which is no longer in such a vague future as it may seem, it has been less than 22 years.
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mongodb 3783

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Can I copy a collection in mongoDB from one database to another by copying the db files directly?
SQL, Database Testing • mongodb nosql database rec languageomme • • Jolied

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You can copy an entire database across in this manner, by copying the files to a new instance, but not collections. You also cannot simply copy the database files from database foo and alter the filenames at the filesystem level (to bar.0, bar.1 etc.) to avoid namespace collisions, the name must remain the same. If you wish to move a single collection (or any subset of collections) rather than a whole database then you will have to use the command you mentioned or use mongodump/mongorestore to do the migration. However, any per-collection method will require rebuilding the indexes from scratch - you only get them in place if you can copy the data files (i.e. move the entire database). If the other collections are relatively small, you could look at copying them elsewhere, out of the current database, leaving just the large collection you wish to move. You can then copy the entire database, and move the database files as mentioned.
Check whether a date is before or after other dates
Software Programming • java data • • inna

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To compare whether a date comes before or after another, use the methods https://docs.oracle.com/javase/8/docs/api/java/util/Date.html#before-java.util.Date- and https://docs.oracle.com/javase/8/docs/api/java/util/Date.html#after-java.util.Date- :if (individuo.getDataNascimento().before(date1) || individuo.getDataNascimento().after(date2)) { etc... } One detail is that I actually think you should use the operator || ("or") instead of && ("and"). Yeah. && verifies whether both conditions are true, and it does not have as a date to be at the same time before 1960 and after 2003 (or is one, or another, both at the same time does not give, so if use && will never enter this if).Another detail is that you don't need to create a new SimpleDateFormat every time. If the format of the strings does not change, just reuse the same:SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy"); String str1 ="31/12/1960"; Date date1 = sdf.parse(str1); String str2 ="31/12/2003"; Date date2 = sdf.parse(str2); An alternative to Java 7 - if you want to use an external library - is https://www.threeten.org/threetenbp/ , one backport the https://docs.oracle.com/javase/tutorial/datetime/index.html (the new Java 8 date API).With this, you can use a more suitable type for each situation. For example, as the birth date only has day, month and year, rather than Date you can use one https://www.threeten.org/threetenbp/apidocs/org/threeten/bp/LocalDate.html :public class SuaClasse { private LocalDate dataNascimento; public LocalDate getDataNascimento() { return dataNascimento; } // etc... } DateTimeFormatter parser = DateTimeFormatter.ofPattern("dd/MM/uuuu"); String str1 = "31/12/1960"; LocalDate inicio = LocalDate.parse(str1, parser); String str2 = "31/12/2003"; LocalDate fim = LocalDate.parse(str2, parser); if (individuo.getDataNascimento().isBefore(inicio) || individuo.getDataNascimento().isAfter(fim)) { // data está antes de "inicio" ou depois de "fim" } It may seem that "it only changed the date class", but the new API has many advantages and improvements with respect to Date, and its use would already facilitate a future migration to Java 8, because it would just change the name of the package org.threeten.bp For java.time (saved one or other specific detail, see more details https://pt.stackoverflow.com/q/177129/112052 and https://pt.stackoverflow.com/q/413649/112052 - in particular, at the end https://pt.stackoverflow.com/a/370367/112052 has some information about the use of backport).
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How to sort the volume with Swift 4.2 dates.
Software Programming • ios swift xcode playground • • Saumya

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as an option through reverse at the date var array = ["29/01/2019", "03/10/2019", "31/01/2019", "29/01/2016", "01/01/2020"] func compareDates(_ first: String, _ second: String) -> Bool { let formatterDate = DateFormatter() formatterDate.dateFormat = "dd/MM/yyyy" return formatterDate.date(from: first)! < formatterDate.date(from: second)! } array.sort { compareDates($0, $1) } // ["29/01/2016", "29/01/2019", "31/01/2019", "03/10/2019", "01/01/2020"] orvar array = ["29/01/2019", "03/10/2019", "31/01/2019", "29/01/2016", "01/01/2020"] array.sort { let formatterDate = DateFormatter() formatterDate.dateFormat = "dd/MM/yyyy" return formatterDate.date(from: $0)! < formatterDate.date(from: $1)! } // ["29/01/2016", "29/01/2019", "31/01/2019", "03/10/2019", "01/01/2020"]
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Find 2 date attributes in a single element
Software Programming • javascript jquery • • Kadyn

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Try this:$('*[data-belongs="2"][data-target="3"]'); Source: https://api.jquery.com/multiple-attribute-selector/
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add in bd a date 2 days after today without knowing and Sunday on mysql php
Software Programming • php mysql date • • Cleofas

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I think what you have to use at this point is the function https://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html#function_dayofweek in ocnjunto with an if, also, to add days you must use the date_add function instead of date_sub :INSERT INTO TABLA_FECHAS (preparar, llamar) VALUES ( '$fecha_actual', IF( DAYOFWEEK('$fecha_actual')=6, DATE_ADD('$fecha_actual',INTERVAL 4 DAY), DATE_ADD('$fecha_actual',INTERVAL 2 DAY) ) );
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Check and remove iteratively without an index
SQL, Database Testing • mongodb • • charlenef

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The current version does not allow for specifying different priorities for different operations. It is likely that maintaining an index on the collection to allow this periodic process to execute much quicker than a full collection scan will give you better overall performance.
Django 2.2 and field of the Date Field model
Software Programming • django • • emmalee

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The problem was that, through the dispatch of the form, the field of the type Date Field could not be empty and the format of the date should be YYYYY-DD-MM (year-day-month). As a result, the function I needed was:views.pyimport time post.beginning_date = time.strftime("%Y-%d-%m") So when I'm dealing with the request, I was able to pass the post.beginning_date and record the post successfully.Come on!for time.strftime is critical to the recording of formatting.
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MongodB cumulated conditionnal array:using map/reduce or aggregation
SQL, Database Testing • mongodb aggregate distinc languaget • • juvenalb

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Start using db.student_confusion.aggregate() with something like this: [ { '$group': { '_id': '$chapter', 'ma': { '$push': { 'target': '$target', 'stimulus': '$stimulus', 'rate': '$rate' } }, 'chapter': { '$first': '$chapter' } } }, { '$project': { '_id': 1, 'chapter': 1, 'matrix': { '$reduce': { 'input': '$ma', 'initialValue': [], 'in': { '$let': { 'vars': { 'tg': '$$this.target', 'vl': [ [ '$$this.stimulus', '$$this.rate' ] ], 'doc': { 'target': '$$this.target', 'v': [ [ '$$this.stimulus', '$$this.rate' ] ] }, 'ind': { '$indexOfArray': [ '$$value.target', '$$this.target' ] } }, 'in': { '$cond': [ { '$gt': [ '$$ind', { '$literal': -1 } ] }, { '$concatArrays': [ { '$filter': { 'input': '$$value', 'as': 'fi', 'cond': { '$ne': [ '$$fi.target', '$$tg' ] } } }, [ { 'target': '$$tg', 'v': { '$concatArrays': [ '$$vl', { '$let': { 'vars': { 'vv': { '$arrayElemAt': [ '$$value', '$$ind' ] } }, 'in': '$$vv.v' } } ] } } ] ] }, { '$concatArrays': [ '$$value', [ '$$doc' ] ] } ] } } } } } } }, { '$project': { 'chapter': 1, 'matrix': { '$map': { 'input': '$matrix', 'as': 'mat', 'in': { '$concatArrays': [ [ '$$mat.target' ], '$$mat.v' ] } } } } } ]
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Specific database for each company
Software Programming • mongodb nodejs expresses • • tahishae

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I don't have enough experience in MERN but if I've managed to make a couple of ribs.In principle I do not think it was necessary to make a BD for each company, I recommend reading https://www.tutorialesprogramacionya.com/mongodbya/detalleconcepto.php?punto=3&codigo=3&inicio=0 so you understand a little what I'll explain nextIn principle I do not think that it was necessary to make a BD for each company, in any case in the same BD creates a collection for companies and another collection for users, and the latter will "relation" them with their corresponding company. Then you as superadmin will load data in the collection companies mainly, and clearly also in users because you would have to define an admin user for each company. Once you have done that in the internal logic you will have to define that for every company admin that loads a new worker will automatically take the admin company and relate it to that of that new user that generated it.For example: you will create the coca-cola company in the collection companies and a user called Pepito as Coca-Cola admin, then Pepito will have two attributes name: nuggling, type:admin, company: Coca-cola (this will bring it from the relationship you defined from the collection users with company) Then when Pepito believes new working users will read that he is coke tail so the new user will put him on coke tail. user: josé, type:worker, company:coca-cola.This as an example, even for entrepreneurs you could create only a collection of users and there itself define their typical attributes as name, email, password etc, and mainly a company attribute and a type attribute, to know if it is admin, superadmin, worker, etc. Let's say the amount of attributes and collections will vary according to the complexity of your project.I leave you in case you need the documentation of mongodb to deepen https://docs.mongodb.com/manual/introduction/ All this of the DB must be defined in node with the help of a module called mongoose and the use of schemas, let you https://apuntes.de/nodejs-desarrollo-web/esquemas-en-mongoose/#gsc.tab=0 some mongoose and schemasSecond, for the management of api I recommend you to learn well nodeJS and the expressJS framework, learn the 4 basic requestspi Rest: get, post, put, delete, and then learn about routes. I leave you some of that. https://juanda.gitbooks.io/webapps/content/api/arquitectura-api-rest.html to give you an ideawith this you can make a CRUD all by "console" say that you will not have graphical interface yet.I leave you a video that explains basicly how to make a basic CRUD from the express installation and creation of the api to the test of the operation with mongodb https://www.youtube.com/watch?v=DqpL5UtJHus Then you should learn something from ReactJs, at first understand the concept of components and properties, leave you a link to that https://es.reactjs.org/docs/components-and-props.html To then be able to do something basic visually and easily I recommend using a CSS framework to do it faster, like for example, materialize, I leave you some materialize https://materializecss.com/ Finally you must learn how to "joint" all of this, and to sum it up I pass a video that explains approximately how to join the frontend with reactJs to the backend by consuming the api you generated previously, the video to https://youtu.be/204v5QXHlmc
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How to test whether unique index can be created in MongoDB?
SQL, Database Testing • mongodb index • • shizuka

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You can use an aggregation query to check for duplicates before trying to create a unique index. For example, if you want to create a unique index on fields a and b: Insert some test data: db.mycollection.insert([ {a: 123, b: 456}, {a: 123}, {a: 123, b: 456}, {c: 789 }, {d: 321 } ]) Find documents with duplicate values: db.mycollection.aggregate([ // Group by the field combination you plan to add a unique index on { $group: { _id: { a: "$a", b: "$b"}, count: { $sum: 1 } }}, // Find any groups which are not unique (more than 1 matching document) { $match: { count: { "$gt": 1} }} ]) Aggregated output for the sample data above would indicate that there are two documents missing the expected fields a and b, and two documents with duplicate values of a and b: { "_id" : { }, "count" : 2 } { "_id" : { "a" : 123, "b" : 456 }, "count" : 2 } In this example I intentionally included some documents with expected fields missing, since those will be indexed as null values if you create a unique index. By default the unique requirement still applies even if one or more fields in the unique index is missing for a given document, because all documents in the collection are added to the index. If you only want the field combination to be unique if both fields are present (or using some other criteria) you can create a Partial Index with Unique Constraint.
How I change a 13-digit timestamp to a readable date
Software Programming • python • • irl

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It's not even a "timespam" (seconds since 1 January 1970It doesn't have 13 digits. It is a chain that concatenates the date and time, in total 14 digits.For example, open_time "02032021175301" It would be:valueformatmonth02%%Day03%dyear2021%YTime17%Hminutes53%Mseconds01%SThe right way to get the time is using datetime.strptime:from datetime import datetime open_time = "02032021175301" fecha = datetime.strptime(open_time, "%m%d%Y%H%M%S") print(fecha.strftime("%c")) 'Wed Feb 3 17:53:01 2021' The formats used with dates and times are in the documenation of https://docs.python.org/3.9/library/time.html#time.strftime .
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How does the MongoDB query optimizer evaluate candidate plans?
SQL, Database Testing • mongodb optimization • • obi

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Does the query optimizer use collections statistics ? The query optimizer does not (as at MongoDB 4.0) use collection statistics. Plan evaluation is based on comparing candidate plans for a given query shape to see which returns the first batch of results (by default 101 documents) with the least amount of overall "work". The works score is a proxy for different effort involved in query stages (index key comparisons, fetching documents, etc). If multiple plans perform identical work during evaluation, there are some small tie-breaking bonuses that can help choose a plan to cache (for example, if a plan is a covered query or does not require an in-memory sort). The winning plan will be cached for future queries matching the same query shape, but will be re-evaluated if performance declines over time or there are other relevant changes (for example, indexes are added/removed). See Query Plans in the MongoDB documentation for a general overview. For best outcomes on common queries you generally want to have an ideal index for your query shape rather than several competing candidate indexes. An ideal index would include the fields in your query and support using the index to sort query results (if you have sort criteria). For a worked example, the Optimizing MongoDB Compound Indexes blog post is a helpful read (note: this uses explain output from an older version of MongoDB, but the general concepts are still applicable). If adding an ideal index isn't possible and the query optimizer isn't able to deterministically chose the best index given your data, you could consider using an index hint to override the query optimization process and force a specific index to be used. Index hints should be used sparingly as they can force suboptimal choices and will ignore any future indexes added that might be more suitable. When we run explain("allPlansExecution"), we get a lot of information about each evaluated plans. But, among following, what are the selection criteria in order of importance to determine the winning plan ? totalKeysExamined, totalDocsExamined, executionTimeMillis, nReturned, memUsage, other... ? From a query scoring perspective, the works value for each query stage is the key indicator. Metrics like totalKeysExamined and totalDocsExamined are useful for a quick comparison of efficiency for the number of results returned (nReturned). Ideally the ratio of totalKeysExamined to nReturned would be 1:1 (a single index lookup for every result), but some complex queries will necessarily have to examine more values. Other execution metrics will vary based on the query stage, but these can provide insight into calculation of the works value for that stage. For a more detailed walkthrough, I recommend the Reading the .explain() Output presentation from Charlie Swanson. If you want to better understand the execution stats for a specific query, I suggest posting a new question on DBA StackExchange with your specific MongoDB server version and output of explain("allPlansExecution"). You may also find it helpful to investigate using a UI tool like MongoDB Compass, which includes a Visual Tree of explain output which is easier to explore than raw JSON.
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MongoDB uses only one index on simple query with sorting
SQL, Database Testing • mongodb index index tuning mongodb 3.0 • • rielyn

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MongoDB 2.6+ will consider index intersection in cases where multiple indexes might improve the query performance, however for sorting the index has to have keys in common with the query predicate. In your scenario, this means an index on {price:1} cannot be used for index intersection unless price is included in the query. So it scans through all the collection ignoring all indexes. What's actually happening according to the query explain() is that the price:1 index is being used to return the results in sorted order via an index scan (IXSCAN). Your compound index would require an in-memory sort of the result set, which may be larger than the size of the in-memory sort buffer (32MB) as you discovered by trying to hint that index. If you can add a limit to your query so the results are smaller than 32MB, the compound index may be usable but not ideal. For your query, the ideal index to support the desired sort order (and an unlimited set of results) is a compound index including the price: db.product.createIndex({"_type": 1, "_collectivity": 1, "own_risk": 1, "price": 1}); For more information, see: Index Intersection and Sort Use Indexes to Sort Query Results Optimizing MongoDB Compound Indexes
vector 2 (2 values from -1.1)
Software Programming • c sharp unity3d 2d • • Demir

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// перевод градуса в радиану float radian = transform.Rotation.z*Mathf.Deg2Rad; Vector2 vector = new Vector2(Mathf.Cos(radian), Mathf.Sin(radian)); Without knowing the geometry of the circumference, you won't go far in the gheimde. What? Sin♪ Cos and Pi I need to know.
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Modify the column with dates on the date
Software Programming • python pandas dataframe datetime • • Cleofas

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As no reproduced data are available, I write the code without verification. The code is not optimal, but it should work on the idea:while True: df_holydays_mask = df['date'].dt.day.isin(holydays) if not holidays_mask.any(): break df.loc[df_holydays_mask, 'date'] = \ df.loc[df_holydays_mask, 'date'] + datetime.timedelta(days=1) The point is for now. df There are holidays, we take these days, and we'll increase all the scope by 1.But it's really nice to have holidays tied to a full date, not just for the day of the month, but it's a little weird for you to just have a day.

Why in Mongo Timestamp 2 dates?

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