Recent questions tagged database

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This question is based on my plan at the thread. My entity-relationship diagram is alt text http://files. ... u/175564/table-problem-3.png See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - Creating the Front End MDE

I created a database for tracking metrics, with some automation tricks (email, .doc,.ppt presentations, etc) with a ... answer so.....Thanks! See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - mySQL - Insert into three tables

I recently asked this question. I have a relational database with three tables. The first containts id's that ... there a more simple way? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - concurrency in hibernate

I have a servlet that does some work for user and then decrement user's credit. When I watch user's credit ... balance2 is "+c2.getBalance()); See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - How to adjust constraints / DB mapping for Map within grails domain class

Following grails domain class: class MyClass { Map myMap } Now for myMap, grails automatically creates a new table for the ... mapping { ... } ? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - listagg data to useable format?

This is my first time working with the LISTAGG function and I'm confused. I can select the data easily enough, ... ) group by course_id; Yields: See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - Can I ask Postgresql to ignore errors within a transaction

I use Postgresql with the PostGIS extensions for ad-hoc spatial analysis. I generally construct and issue SQL queries by ... time I make a typo. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - Python - SqlAlchemy: Filter query by great circle distance?

I am using Python and Sqlalchemy to store latitude and longitude values in a Sqlite database. I have created a ... What am I doing wrong? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - How to properly avoid Mysql Race Conditions

I know this has been asked before, but I'm still confused and would like to avoid any problems before I go ... is avoided. Thanks in advance. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - Do i have to use _ID as a SQlite primary key? and does it have to be an INT? (Android Dev)

This is probably a silly question but i haven't been able to find the answer yet. I want to use a TEXT ... close? haha sorry i am trying! See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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814 views

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database - Setting default-time-zone on MySql Server via PhPMyAdmin

I have a shared hosting mySql instance which has it's system_time_zone set to Pacific Standard Time and it's ... your help and advice, Martin See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - Changing a column from string to string array in postgresql

The following is a snippet of a table called "containers". Column | Type | Modifiers ---------------- ... be cast to type character varying[] See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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651 views

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database - Method of finding gaps in time series data in MySQL?

Lets say we have a database table with two columns, entry_time and value. entry_time is timestamp while value can be ... and old) with a query? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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757 views

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database - Rails 3, ActiveRecord, PostgreSQL - ".uniq" command doesn't work?

I have following query: Article.joins(:themes => [:users]).where(["articles.user_id != ?", current_user ... not. Exist any alternative? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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881 views

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database - What's the point of a candidate key?

I'm fairly new to database management and this question never seems to be answered in more than one sentence. All ... not seem "minimal" to me. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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776 views

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database - Avoiding inserting duplicate rows in mySQL

I have a table with an auto_inc id (primary key). I am trying to avoid the insertion of duplicate rows. ... but all other fields are identical. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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976 views

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database - Classic ASP - SQL Server 2008 Connection String using Windows Authentication

This should be painfully simple, but I cannot come up with a working connection string for a local copy of ... in the right direction? Thanks! See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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905 views

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database - How to create multi environment DB's with Firestore

I've been looking at how to create multiple Firestore instances in Firebase, I need different Db's for prod, ... pay Triple? Thanks in advance See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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858 views

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database design - Why single primary key is better than composite keys?

Why is the rejection of composite keys in favor of all tables using a single primary key named id? ... simplifies the situation significantly.* See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database - why would you use WHERE 1=0 statement in SQL?

I saw a query run in a log file on an application. and it contained a query like: SELECT ID FROM ... that is bound to return nothing? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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695 views

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database - Is it better to store telephone numbers in some canonical format or "as entered"?

Storing a telehone number in some kind of canonical format has several advantages from a programmers point of view, but it ... 's the way to go? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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657 views

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database - Is there an equivalent for SQL Server's @@error in MySQL

I want to run an update query against a production database and as good little developer I am trying to make ... single query in a transaction. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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742 views

1 answer

database - How do I configure my MongoDB to take UTF-8 into account?

I want to deal with UTF-8 now. I haven't done any special configs. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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655 views

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database - How sql with-recursive statement interpreted?

I would like to ask get some help about understanding how "with recursive" works. More precisely WHY the anchor ... Technet : structure of CTE See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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898 views

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database - postgresql: data type for md5 message digest?

I want to use the MD5 message digest of some string as the primary key of a table. What datatype should I use ... should I write for the field? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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892 views

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database schema - Add constraint to existing SQLite table

I'm using SQLite, which doesn't support adding a constraint to an existing table. So I can't do something like ... add a table with that schema? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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815 views

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database - how to select first N rows from a table in T-SQL?

Is there any way to select, for example, first 10 rows of a table in T-SQL (working MSSQL)? I think I ... rownum<=10 But what about MSSQL? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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863 views

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database - Do conditional INSERT with SQL?

I have a database that is updated with datasets from time to time. Here it may happen that a dataset is ... not exist? I'm using SmallSQL See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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