Tag：Data sheet
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Time：2021-12-29
1. Enter the path with mongoexport CD / usr / local / mongodb / bin (there is mongoexport mongoimport mongodump mongorestore) 2. Export data table ./mongoexport -d adverseDrugReaction -c directions -o ../directions.json *- D followed by database -C followed by collection -O is the exported file name. Go to the mongodb folder and find directions […]
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Time：2021-12-28
In SQL, cardinality is defined as the number of unique data in a data column. High cardinality is defined as that the data in a data column is basically not repeated, or the repetition rate is very low. For example, our common identification number, email address, user name, etc. can be considered as high cardinality […]
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Time：2021-12-28
get ready: The tools used for database backup and recovery are mongodump and mongorestore. The tools used for data table import and export are mongoimport and mongoexport. Therefore, you must enter the files with these four tools. Generally, these four files are under / usr / local / mongodb / bin () 1、 Backup and […]
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Time：2021-12-22
Note: translation,Original addresshttp://blog.safaribooksonline.com/2013/11/06/extending-the-django-orm/ Django’s object relational mapping (ORM) builds a bridge between code and database. In this article, I intend to briefly talk about what ORM is and how to use it. The most important thing is how to customize and extend ORM with special SQL.Finally, I would like to say a few points about […]
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Time：2021-12-19
Generally, when developing an application, if it involves the addition, deletion, modification and query of the database, we generally need to check the database to determine whether there is a problem with our inserted data or our query syntax; So how to view the database? The common method is to find the database under data […]
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Time：2021-12-19
Next, we need to continue to optimize, such ashttps://feed43.com/In that way, you can enter the web URL to generate RSS feed, and set the update time according to your actual needs. From: spend 2 hours on an RSS generatorhttps://mp.weixin.qq.com/s/mRjoKgkq1PoqlVgOw8oRYw Today, try to finish how you can set the update interval according to your actual needs. […]
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Time：2021-12-18
Type 10 tuple and list filtering Reference list We already know that we can use DAX to calculate the value of a column in the table to perform aggregation, calculate or retrieve (query) numbers, etc., but finally:All calculations will involve columns or tables (single list or multiple lists). Therefore, we say that the first syntax […]
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Time：2021-12-14
Test driven development has always been mentioned, but it is always unclear how to implement it. Here, we will implement a simple registration function through laravel 5.6 to talk about how to implement test driven development Clarify requirements and function analysis This is the first step of test driven development. First of all, you need […]
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Time：2021-12-13
Laravel uses UUID Recently, when writing small programs, the back-end needs to provide API interfaces. The back-end uses the API interfaces developed by laravel. For many factors such as data security, simple UUID integration is realized in the returned data. Software version: laravel 5.6 Since laravel 5.6 comes with UUID package support, we only need […]
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Time：2021-12-6
1、 Write at the beginning Vivo cloud service provides users with the ability to back up contacts, SMS, notes, bookmarks and other data on their mobile phones. The underlying storage adopts MySQL database for data storage. With the development of vivo cloud service business, the number of cloud service users is growing rapidly, and the […]
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Time：2021-12-4
1、 Transpose id name count 12 Joe 100 12 Neo 200 12 Lve 300 SELECT Listing, GROUP_ Contact (case when column name = specific value then column name end) as new name, GROUP_ Contact (case when column name = specific value then column name end) as new name, GROUP_ Contact (case when column name = […]
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Time：2021-11-11
After two months of efforts, matrixdb 4.3 was finally officially unveiled in early November to create six new features with comprehensive performance. 1. Continuous gathering and grand launch Continuous aggregation is a feature often used in time series scenes. It is used to frequently obtain the aggregation values of data points in the time window. […]
