We recently saw that we can benefit from using JSON documents with MySQL HeatWave cluster in OCI (HeatWave accelerator for MySQL Database Service).

However sometimes the data can’t be loaded to HeatWave Cluster or the query cannot use it.

And this is not always easy to understand why. Let’s get familiar on how to find the info.

Data not loaded in HW Cluster

Let’s see an example with this table (collection):

SQL > show create table listingsAndReviews\G
*************************** 1. row ***************************
       Table: listingsAndReviews
Create Table: CREATE TABLE `listingsAndReviews` (
  `doc` json DEFAULT NULL,
  `_id` char(28) GENERATED ALWAYS AS
 (json_unquote(json_extract(`doc`,_utf8mb4'$._id'))) STORED NOT NULL,
  `_json_schema` json GENERATED ALWAYS AS 
  (_utf8mb4'{"type":"object"}') VIRTUAL,
  PRIMARY KEY (`_id`),
  CONSTRAINT `$val_strict_B70EB65BDDBAB20B0EE5BB7532C9060C422A06F8` …

Since the release of MySQL 8.0, the MySQL X Dev API has provided users with the convenient ability to utilize MySQL without the need to write a single line of SQL!

MySQL X Dev API brings the support for CRUD operations on JSON documents that are stored in MySQL. MySQL Document Store is ACID compliant and is compatible with everything MySQL like replication, InnoDB Cluster, …

The MySQL X Dev API is available using the MySQL X Protocol, listening by default on port 33060.

If you are interested in learning more about MySQL Document Store, please refer to the these presentations [1], [2], [ …

One of my students asked how you could get JSON data out in tabular format. I said they should look at Øystein Grøvlen’s JSON_TABLE – Best of Both Worlds blog post from 2018. Unfortunately, the student wanted another example with the Video Store model that we use in class.

For clarity, all path definitions start with a $ followed by other selectors:

• A period followed by a name, such as $.website
• [N] where N is the position in a zero-indexed array
• The .[*] wildcard evaluates all members of an object
• The [*] wildcard evaluates all members of an array
• The prefix and suffix wildcard, **, evaluates to all paths that begin with the named prefix and end with the named suffix

So, here’s a quick supplement to what’s already there. It assumes you created an …

Yesterday, I wrote a blog post that showed you how to write a query returning a JSON structure for a 1:many relationship. The relationship was between the member and contact table. It returns one account_number from the member table and a list of first_name and last_name columns from the contact table in a JSON structure.

One of my students asked why I choose to strip the backslashes with Python, and my reply was the SQL was already complex for most blog readers. The student asked but how would you do it in SQL. OK, that’s a fair question for two reasons. First, you don’t need to do in your local programs because it’ll run faster on the server. Second, if you strip the backslashes you can insert it into a standard JSON column. This blog post will show you how to do both.

You would use three REGEXP_REPLACE function calls, like:

Are they really tricks or simply basic techniques combined to create a solution. Before writing these mechanics for using native MySQL to create a compound JSON object, let me point out that the easiest way to get one is to use the MySQL Node.js library, as shown recently in my “Is SQL Programming” blog post.

Moving data from a relational model output to a JSON structure isn’t as simple as a delimited list of columns in a SQL query. Let’s look at it in stages based on the MySQL Server 12.18.2 Functions that create JSON values.

Here’s how you return single row as a JSON object, which is quite straightforward:

SELECT JSON_OBJECT('first_name',c.first_name,'last_name',c.last_name) AS json_result
FROM   contact c
WHERE …

Let’s start with some info about how MySQL Document Store handles JSON documents.

Document Store and CRUD

We know that MySQL 8.0 Document Store handles JSON documents with CRUD operations. We can add, delete and modify those documents very easily:

 JS >db.mycollection.find()
{
    "_id": "0000624d3e890000000000000001",
    "name": "my_iot1",
    "type": "sensor",
    "capabilities": "{'temperature':'true','humidity':'true'}"
}
{
    "_id": "0000624d3e890000000000000002",
    "name": "my_iot2",
    "type": "sensor",
    "capabilities": "{'temperature':'true'}"
}
2 documents in set (0.0007 sec)

To modify a document, the modify method can be used in different ways:

As illustrate above, we have:

• set()
• …

As you know, MySQL 8.0 can be used as JSON Document Store to store your documents without being linked to any schema. You can also use CRUD operations to deal with these documents using the MySQL X DevAPI.

Of course in documents, it’s possible to also store temporal attributes like date, time, datetime, …

Let’s see how we can deal with such attributes.

This is an example of a collection of documents with a datetime attribute createdOn:

As those attributes don’t have a real type, can we use the createdOn attribute as if it was a real datetime field ?

Let’s try to get all the documents have a created data > '2021-12-02':

We can see that the document “dave” has been filtered out. However, we can see that “kenny” and “miguel” are also present… and this is correct as …

In the article, we are going to discuss data types including string, numeric, date and time, spatial, and JSON supported by MySQL. Also, we’ll provide examples of their usage and see how to change a data type for the table column using dbForge Studio for MySQL. Contents What is a Data Type Data Types in […]

The post Data Types in MySQL: Tutorial and Full List with Examples of Data Formats appeared first on Devart Blog.

Database architecture and design are becoming an increasingly lost art. With new technologies and the push towards faster development cycles, people continue to take shortcuts, often to the detriment of long-term performance, scalability, and security. Designing how your application stores, accesses, and processes data is so fundamentally important, it can not be overlooked. I want people to understand that early design choices can have a profound impact on their applications. To that end, I will be exploring database design principles and practices over the next several months. I am starting with every developer’s favorite data format: JSON!

It seems that almost every database over the last few years has introduced various degrees of support for storing and interacting with JSON objects directly. While these features are designed to make it easier for application developers to write code faster, the implementations of each implementation …

Introduction In this article, I’m going to explain how we can index JSON columns when using MySQL. While other relational database systems provide GIN (Generalized Inverted Index) indexes, MySQL allows you to index a virtual column that mirrors the JSON path expression you are interested in indexing. Database table Let’s assume we have the following database book table: The properties column type is json, so we can store JSON objects as book properties. Querying MySQL JSON columns without an index If we try to filter one record by its associated title attribute... Read More

The post How to index JSON columns using MySQL appeared first on Vlad Mihalcea.