Recent questions tagged Database

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database design - Facebook "like" data structure

I've been wondering how facebook manages the database design for all the different things that you can "like". If ... do they store the likes? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - MySQL: low cardinality/selectivity columns = how to index?

I need to add indexes to my table (columns) and stumbled across this post: How many database indexes ... cardinality/selectivity of the values? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - How can I run just the statement my cursor is on in SQL Server Management Studio?

As a long time Toad for Oracle user, I have gotten used to hitting Ctrl+Enter and having just the statement ... the statement under the cursor. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - Cloud Firestore deep get with subcollection

Let's say we have a root collection named 'todos'. Every document in this collection has: title: String subcollection named ... / ... }); }); See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - PostgreSQL how to see which queries have run

I have a PostgreSQL DB at my computer and I have an application that runs queries on it. How can I see ... use a Linux computer and pgadmin. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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953 views

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database - Django Model - Case-insensitive Query / Filtering

How can I query/filter in Django and ignore the cases of my query-string? I've got something like ... MyClass.objects.filter(name=my_parameter) See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - Neo4j: Step by Step to create an automatic index

I am creating a new Neo4j database. I have a type of node called User and I would like an index on the ... playing in the Power Tool Console. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - Unique BooleanField value in Django?

Suppose my models.py is like so: class Character(models.Model): name = models.CharField(max_length=255) ... (admin) form levels! See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - SQL how to increase or decrease one for a int column in one command

I have an Orders table which has a Quantity column. During check in or check out, we need to update that Quantity ... way to do this? thanks, See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - Create mysql table directly from CSV file using the CSV Storage engine?

I just learned that MySQL has a native CSV storage engine which stores data in a Comma-Separated-Value file per ... is uploaded by the user? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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636 views

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database - What is the difference between DBMS and RDBMS?

After reading some answers on different websites I am confused now. So, it would be helpful to mention the ... and any relation between them. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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683 views

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database - How do I drop a table from SQLite3 in DJango?

I made a model, and ran python manage.py syncdb. I think that created a table in the db. Then I realized that ... 't figure out how to do that. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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840 views

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database - IntelliJ IDEA 10 generate entity (POJO) from DB model

How can I generate entity (POJO) from database model using IntelliJ IDEA 10. I create "Data source" in IntelliJ ... can I generate the POJO. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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661 views

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database - Rename a table in MySQL

Renaming a table is not working in MySQL RENAME TABLE group TO member; The error message is #1064 - You have ... but not with the table group. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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641 views

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database - Handling very large data with mysql

Sorry for the long post! I have a database containing ~30 tables (InnoDB engine). Only two of these tables, ... =COMPACT Thanks for your time, See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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712 views

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database - How do I automatically update a timestamp in PostgreSQL

I want the code to be able to automatically update the time stamp when a new row is inserted as I can ... varchar(200), timestamp timestamp ) See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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586 views

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database - What does GRANT USAGE ON SCHEMA do exactly?

I'm trying to create a Postgres database for the first time. So this is probably a stupid question. I ... privilege requirements are also met"? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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744 views

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database - Run PostgreSQL queries from the command line

I inserted a data into a table....I wanna see now whole table with rows and columns and data. How I can display it through command? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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765 views

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database - How to work with Git branches and Rails migrations

I am working on a rails app with quite a few git branches and many of them include db migrations. We try to ... databases (a few GBs in size). See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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655 views

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database - Common MySQL fields and their appropriate data types

I am setting up a very small MySQL database that stores, first name, last name, email and phone number and ... phone number, email and address? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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702 views

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database - What is the difference between Non-Repeatable Read and Phantom Read?

What is the difference between non-repeatable read and phantom read? I have read the Isolation (database systems) article ... be used? And why? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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782 views

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database - Sequelize.js: how to use migrations and sync

I'm close to having my project ready to launch. I have big plans for after launch and the database ... with no legacy starting database? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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783 views

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database - CAP theorem - Availability and Partition Tolerance

While I try to understand the "Availability" (A) and "Partition tolerance" (P) in CAP, I found it ... P and the difference between them? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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675 views

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database - Excel - VBA Question. Need to access data from all excel files in a directory without opening the files

So I have a "master" excel file that I need to populate with data from excel files in a directory. I just ... move down the list of files? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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805 views

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database - How do you fetch all documents (including non-existent ancestor documents) in a Firebase collection?

I am trying to pull all the documents in the collection 'users', but it only pulls 'fred' and 'lisa', and ... is there a more elegant solution? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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652 views

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database - Databse architecture (single db vs client specific db) for Building Enterprise Web (RIA) application on cloud

We are working on rewriting our existing RIA and redesigning our database to re-architect it's design. Now ... Amazon cloud for hosting. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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904 views

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database - Are Cloud Firestore queries still case sensitive?

Firebase Realtime Database accept queries with strings in case sensitive manner. Does this still apply for Firestore? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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564 views

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database - SQLite android column not found

my code is correct is assume but even though it gives error coloumn not found for _hour & _min: package com. ... means any space or something? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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