CREATE TABLE tableName ( jsonData CHAR(250) -- or VARCHAR, TEXT, BLOB ); INSERT INTO tableName VALUES ( '{ "name": "User1", "age": 41}' ); SELECT * FROM tableName; { "name": "User1", "age": 41}
SELECT * FROM tableName WHERE jsonData REGEXP 'User1';
CREATE TABLE tableName ( jsonData JSON ); INSERT INTO tableName VALUES ( '{ "name": "User1", "age": 41, "name": "User2"}' ); SELECT * FROM tableName; {"age": 41, "name": "User2"}
- ابتدا بررسی خواهد شد که سند JSON معتبر باشد؛ در غیر اینصورت ذخیرهسازی با مشکل مواجه خواهد شد.
- از فیلدهایی که کلید تکراری دارند، صرفنظر خواهند شد. در مثال بالا دوبار فیلد name را مقداردهی کردهایم. در اینجالت key/value دوم لحاظ شدهاست. البته میبایستی اصل first key wins لحاظ میشد، اما این مورد به عنوان یک باگ گزارش شدهاست و در نسخههای 8 به بعد رفع شدهاست (https://forums.mysql.com/read.php?3,660500,660500 - https://bugs.mysql.com/bug.php?id=86866).
- فاصلههای اضافی بین کلیدها حذف شدهاند.
- برای جستجوی بهتر، کلیدهای آبجکت JSON به صورت مرتب شده ذخیره شدهاند.
{ "id": "1", "sku": "asdf123", "name": "Lorem ipsum jacket", "price": 12.45, "discount": 10, "offerEnd": "October 5, 2020 12:11:00", "new": false, "rating": 4, "saleCount": 54, "category": ["fashion", "men"], "tag": ["fashion", "men", "jacket", "full sleeve"], "variation": [ { "color": "white", "image": "/assets/img/product/fashion/1.jpg", "size": [ { "name": "x", "stock": 3 }, { "name": "m", "stock": 2 }, { "name": "xl", "stock": 5 } ] }, { "color": "black", "image": "/assets/img/product/fashion/8.jpg", "size": [ { "name": "x", "stock": 4 }, { "name": "m", "stock": 7 }, { "name": "xl", "stock": 9 }, { "name": "xxl", "stock": 1 } ] }, { "color": "brown", "image": "/assets/img/product/fashion/3.jpg", "size": [ { "name": "x", "stock": 1 }, { "name": "m", "stock": 2 }, { "name": "xl", "stock": 4 }, { "name": "xxl", "stock": 0 } ] } ], "image": [ "/assets/img/product/fashion/1.jpg", "/assets/img/product/fashion/3.jpg", "/assets/img/product/fashion/6.jpg", "/assets/img/product/fashion/8.jpg", "/assets/img/product/fashion/9.jpg" ], "description": { "shortDescription": "Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur.", "fullDescription": "Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur? Nor again is there anyone who loves or pursues or desires to obtain pain of itself, because it is pain, but because occasionally circumstances occur in which toil and pain can procure him some great pleasure. To take a trivial example, which of us ever undertakes laborious physical exercise, except to obtain some advantage from it? But who has any right to find fault with a man who chooses to enjoy a pleasure that has no annoying consequences, or one who avoids a pain that produces no resultant pleasure?" } }
SELECT JSON_PRETTY( JSON_EXTRACT(data, "$.category") ) FROM experiments.productMetadata; /* [ "fashion", "men" ] [ "fashion", "women" ] [ "fashion", "men" ] */
JSON_EXTRACT(data, "$.tag[1]") JSON_EXTRACT(data, "$.description.shortDescription")
SELECT JSON_EXTRACT(data, "$.*.shortDescription") FROM experiments.productMetadata;
SELECT JSON_KEYS(data) FROM experiments.productMetadata; -- ["id", "new", "sku", "tag", "name", "image", "price", "rating", "category", "discount", "offerEnd", "saleCount", "variation", "description"] -- ["id", "new", "sku", "tag", "name", "image", "price", "rating", "category", "discount", "saleCount", "variation", "description"]
SELECT JSON_KEYS(data, "$.description") FROM experiments.productMetadata; -- ["fullDescription", "shortDescription"] -- ["fullDescription", "shortDescription"]
SELECT JSON_CONTAINS(data, "10", "$.discount") FROM experiments.productMetadata; -- 1 -- 0
SELECT JSON_CONTAINS_PATH(data, "one", "$.description", "$.address", "$.website") FROM experiments.productMetadata;
SELECT JSON_SEARCH(data, 'one', 'fashion') FROM experiments.productMetadata; -- "$.tag[0]" -- "$.tag[0]"
مقایسه HTTP/2 PUSH و HTTP Preload
HTTP/2 PUSH is a feature that lets a server pre-emptively push resources to the client (without a corresponding request). HTTP Preload is a way to indicate to the browser resources it would require while loading the current page. In this post, we will discuss the key differences between PUSH and Preload, with a detailed explanation of which one to choose based on your use case.
There are two MySQL providers for Entity Framework Core:
- The official one from MySQL: MySql.Data.EntityFrameworkCore. As of now, the latest version is 8.0.19, and works with Entity Framework Core 2.1 (and probably also 2.2). Since EF Core 3.0 is a major version with breaking changes, you cannot use it with this provider.
- The Pomelo provider: Pomelo.EntityFrameworkCore.MySql. There is a 3.1 version of this provider.
In other words, if you want to use EF Core 3.0/3.1 with MySQL, at this point you need to use the Pomelo provider (or wait for the official MySQL one to get released).
داستان مخزن کد Definitely Typed
Angular 8 منتشر شد
کتاب رایگان UWP Succinctly
- Introduction
- The Essential Concepts: Visual Studio, XAML, and C#
- Creating the User Interface: The Controls