How to Query a Database and Write the Data to JSON

MySQL 5. Normalization is a technique used to optimize the database structure. If you have clear relational data requirements, use appropriate single-value fields.

JSON should be used sparingly as a last resort. JSON value fields cannot be indexed, so avoid using it on columns which are updated or searched regularly.

In addition, fewer client applications support JSON, and the technology is newer and possibly less stable than other types. Consider a shop selling books. A book table will have an ID, ISBNtitle, publisher, number of pages and other relational data which applies to all books.

Presume we want to add any number of category tags to any book. We could achieve this in SQL using:. Note that JSON columns cannot have a default value, be used as a primary key, be referenced as a foreign key or have an index. For example, our book tags can be passed as an array:. It returns 1 when a match is found, e. It is passed the JSON document being searched, 'one' to find the first match or 'all' to find all matches, and a search string, e. A JSON path targets values and can be used to extract or modify parts of a document.

For a more complex example, presume we have a user table with JSON profile data, e. These include:.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I am trying to retrieve the data from database and display it out in jSON format. I am using MySQl as a database. Below is the data result from Database table with select query:. I need help to display the data in correct JSON format. Any suggestions are always welcome. Learn more. Retrieving Data from Database and show in the json format Ask Question.

Asked 1 year, 11 months ago. Active 1 year, 11 months ago. Viewed times. Below is my java code in JsonServlet. IOException; import java. PrintWriter; import java. Connection; import java. DriverManager; import java. PreparedStatement; import java. ResultSet; import javax. ServletException; import javax.

how to retrieve data from database in json format using java

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how to retrieve data from database in json format using java

Post as a guest Name. Email Required, but never shown. The Overflow Blog. Podcast Programming tutorials can be a real drag. Featured on Meta.Comment 6. JSON JavaScript Object Notation is a lightweight data interchange format that is now being used as a profound and efficient way of gathering, collecting, or share data among applications and interfaces.

The data that is parsed from a JSON API is in the form of objects that need to be converted into their respective data formats as acceptable by the system. The answer to that would be now a days maximum of the client data is available over the web as it is not prone to data loss. More over clients built around JSON API are able to take advantage of its features around efficiently caching responses, sometimes eliminating network requests entirely.

The benefit of doing this is that we will be able to harness the properties of the HttpURLConnection class to validate features. For example, set the request type or check the status of the response code:. Step 4 Open a connection stream to the corresponding API. Step 6 Now we need to perform a check so that if the response code is notwe throw a runtime exception, or otherwise carry on the rest of the procedure. The structure would be like this:. Step 7 I have used the method scanner to read each line from the API and fetch the data in string format.

Now you have all the data with you from the API. Somehow, it looks a bit unstructured, and you will definitely need the data categorically and not all the data as a whole.

How to Insert/Retrieve JSON Data to/from Database using PHP

For this, you need to parse this data into a JSON object. In some cases, you need to store the data in JSON array as well. Download the required jar files and configure its class path in the system. If you view the JSON structure, it will be something like this:. I would now like to get the corresponding values under the results array. Here is how you do it:.

Let us dig a bit deeper. Now we parse the JSON data present in the string format:. See the original article here. Integration Zone. Over a million developers have joined DZone. Let's be friends:. DZone 's Guide to. Free Resource.

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How to Read JSON Data and Insert it into a Database

JSON is quite simple, easy and light-weight format for exchanging and storing data from and to database. The number of columns should not be less than the required fields in the JSON file. In my case, I have created a table with the required fields as shown below:. Once you have created a database having table with the required fields, the next step is to connect that database with the PHP file. For this, a PHP file is to be made, which is given as:. Please Fix the Issue! Once connection is made and a database is selected, then you can go further for the next operation, otherwise an error will be displayed for fixing the issues.

This function reads the contents of the given file to a string. The next step is to fetch the decoded values and store it in variables of PHP. This can be done by fetching one-by-one and storing it in different variables. It is important to note that the names of table columns in the database should be written correctly as present in the database otherwise the data will not be inserted in the database. Once you are done with the above defined steps, then there should not be any problem in inserting JSON data in database.

Run the above code and you will get the output as follow:. Refresh your database and you will see that data is inserted successfully. The output for the database will be as follow:. You can see in the above snapshot that the data is inserted properly in the relevant columns. If you want to add more data in the columns of the table, change the data in the JSON file or add another JSON file with different name and run the code again.

The next step is the reverse of the above i. In this part, we are going to extract the data that is being stored in database and put in the provided JSON file.Previous entries in this blog have shown how you can store and query existing JSON data. Since Oracle Database release In this entry we will walk you thru the 4 operators and show you how a combination can create a complex JSON instance.

But first the use cases; why would someone want to create JSON from relational data in the Oracle database? A typical use case expressed by customers is to web-enable a legacy relational application. In this case the data is stored relationally aka in tables and columns and a new browser-based application benefits if the data coming from the database is in JSON format.

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Instead of relying on some middleware code to turn the data into JSON wouldn't it be nicer and faster if the database could perform the conversion? Let's take the following as as example: an very simple model of a purchasing system. Customers can submit orders and orders consists of one or multiple items from a catalog. Because of the normalization of the data some tables are hard to read; you need to follow the relationships expressed by the id's to find out the name of ordered items for example.

The want the JSON we generate from this data to be a bit more readable - so we will perform lookups. The data field used the ISO data format. Where therefore nest the two operators. Now, nesting the JSON generation functions allow us to create one JSON instance that reflects the state of all four tables; this means that we need to join the four tables - again, a strength of a hybrid system that provides you native JSON processing without sacrificing relational features likes join.

Also, SQL allows us to do calculations, like counting the number of orders and multiplying the price of a single item with its quantity. The number of rows is driven by the 'customers' table, then for each customer we query the other three table to find the orders and the prices and names of the ordered items:. It specifies how a NULL value is handled. In the example we want to avoid printing an empty array for customers who have not ordered anything.

We often get asked about the possibility of using partitioning with SODA collections. Today, this can be done with just a bit of initialJSON JavaScript Object Notation is a lightweight, text-based, language-independent data exchange format that is easy for humans and machines to read and write. JSON can represent two structured types: objects and arrays.

An array is an ordered sequence of zero or more values.

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The values can be strings, numbers, booleans, null, and these two structured types. Below is a simple example from Wikipedia that shows JSON representation of an object that describes a person.

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Getting Started : You need to download the json-simple Hence in our output file, order is not preserved. This article is contributed by Gaurav Miglani. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above. Writing code in comment? Please use ide.

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how to retrieve data from database in json format using java

Load Comments. FileNotFoundException; import java. PrintWriter; import java. LinkedHashMap; import java.

how to retrieve data from database in json format using java

Map; import org. JSONArray; import org. FileReader; import java. Iterator; import java. JSONObject; import org.Simplify data security, automation, server-to-server file transfers, and more. Strong encryption and authentication technology for critical file transfers. Asymmetric cryptology for protecting confidential files at rest and in motion. Simple and secure interfaces for user-to-user file sharing and collaboration. Build automated workflows to move files effortlessly between internal systems, users, and trading partners.

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In this tutorial, you will learn how to query two database tables, join the data using a conditional expression, and write the data to a JSON file.

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Start a free trial and test it out for 30 days. JSON data is represented in a logical, organized, and easy-to-access manner. To begin, create a new Project following the Getting Started with Projects tutorial. The orders database table will be queried first. With the SQL wizard, you can choose schemas librariestables physical filescolumns fieldscolumn headings, "where" clauses and "order by" criteria.

See the SQL Wizard tutorial for more information. In the Object element click the Add button in the sub-menu, and then select Array. The Array element iterates through each row in a RowSet variable. This array will contain multiple objects.

In the Write Array element, click the Add button in the sub-menu, and then select Object. On the Object element, specify a Name. In the Object element, click the Add button in the sub-menu, and then select Field. As needed, add additional fields, from the Add link in the sub-menu by selecting the Add Same option.

Follow the same process above, specifying the field name that will appear in the output file along with the appropriate column index of the RowSet variable. Click the Save button when finished. The following image illustrates the Project Outline so far:. Select the Object element of the orders array. Click the Add button and select Array. Add the Object that will contain the customer fields. Select the customers array, click the Add button, and select Object.

To join data from both tables using the 'custid' as a qualifier, add a conditional expression to the new Object element. Secure data exchange with trading partners and applications in the cloud. Solutions Comprehensive File Transfer Solutions. Managed File Transfer Simplify data security, automation, server-to-server file transfers, and more.

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