Connecting to a PostgreSQL database using Flexmonster Data Server

This tutorial describes how to connect to a PostgreSQL database using Flexmonster Data Server – a special server developed by Flexmonster. This server aggregates your data and then passes it to Flexmonster Pivot in a ready-to-show format.

Prerequisites

Flexmonster CLI
Install it with the following command:
```
npm install -g flexmonster-cli
```

Now follow the steps below to connect to PostgreSQL using the Data Server.

Step 1. Install Flexmonster Data Server

Get the Data Server with the flexmonster add fds command:

flexmonster add fds -r

This command installs and runs the Data Server as a Windows/Unix service. Besides, the command also installs Flexmonster Admin Panel — a graphical user interface for the Data Server.

The Data Server's files can be found in the flexmonster-data-server/ folder in your working directory.

There are also alternative ways to install the Data Server:

Step 2. Add a new index

Now let's create a new index for your data.

Open Flexmonster Admin Panel and go to Indexes > Add New Index. Then, fill in the following fields:

Name. This field defines the index name. It will be used to configure the connection on the client side.
Type. This drop-down menu contains possible data source types. In this case, select Database.
Database type. Select the database. In this case, it should be PostgreSQL.
Connection string. Specify the connection string to your database here. Have a look at the examples of different connection strings for PostgreSQL.
Click Test to check whether the provided connection string is correct.
Note that there are specifics of setting passwords with special characters in the connection string. The Data Server parses such passwords correctly unless the password contains ; or ". These symbols are treated as delimiters, so if your password contains them, enclose it in single quotes (e.g., Pwd='123;"45').
Query. Specify an SQL query to define the subset of data that the Data Server should fetch. The Query can contain a stored procedure.
Refresh time. It defines how often the Data Server should reload the data from the database. The refresh time should be specified in minutes.
By default, the refresh time is 0, which means the Data Server will not reload the data.

Your configurations should look similar to the following:

Sample configuration of a PostgreSQL index

When the index configuration is complete, click Create. The index will be automatically added to your index pool.

Step 3. Embed the component into your webpage

If Flexmonster is not yet embedded, set up an empty component in your webpage:

In pure JavaScript

Complete the Quick start guide. Your code should look similar to the following example:

let pivot = new Flexmonster({
  container: "pivotContainer",
  componentFolder: "node_modules/flexmonster/",
  toolbar: true
});

In Angular

Complete the Integration with Angular guide. Your code should look similar to the following example:

<fm-pivot 
 [toolbar]="true">
</fm-pivot>

In React

Complete the Integration with React guide. Your code should look similar to the following example:

<FlexmonsterReact.Pivot
 toolbar={true}
/>

In Vue

Complete the Integration with Vue guide. Your code should look similar to the following example:

<Pivot
 ref="pivot"
 toolbar>
</Pivot>

Step 4. Configure the report

On the client side, the report should be configured as follows:

let pivot = new Flexmonster({
  container: "pivotContainer",
  componentFolder: "node_modules/flexmonster/",
  toolbar: true,
  report: {
    dataSource: {
      type: "api",
      url: "http://localhost:9500",
      index: "index-database"
    }
  }
});

Note The index must match the name of the index defined in step 3 (e.g., "index-database").

When Flexmonster Pivot requests the data, Flexmonster Data Server sends the response and then caches it. In case the component sends the same request once again, the server responds with the data from its cache. The Data Server clears the cache when restarted.

The Data Server’s cache has a memory limit. When the cache does not have enough memory for a new response, the Data Server server deletes one of the previously cached responses.

Note You can manage the cache size via the Cache size limit configuration.

Calling a stored procedure

Follow the steps below to call a stored procedure in the Data Server:

Step 1. Create a stored procedure.

Step 2. When adding a new index, call the stored procedure in the Query field:

call storedProcedure()

Learn more about calling stored procedures in PostgreSQL.

Note Stored procedures allow executing any valid SQL query from the Data Server. To avoid unauthorized access to the database, create a database user with read-only access rights and specify this user in the connection string.

What’s next?

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