Display All SQL Method

The displayAll method retrieves data from a table within a specified data source (database). It allows you to apply filters, sorting, pagination, and grouping to control the output.

Parameters:

1. dataname (Data Source Name):

   • Replace 'your_data_source_name' with the actual name of your data source (database).
   • This parameter specifies the database where the table exists.

2. displayOptions:

   • The displayOptions object contains various settings for retrieving data:
     • filters (Optional):
       • Specifies filters to apply to the data.
       • Example: { tableName: { column: 'value' } }
     • sortOrder (Optional):
       • Specifies the sort order ('asc' or 'desc').
       • Example: 'desc'
     • page (Optional):
       • Specifies the page number for pagination.
       • Example: 1
     • pageSize (Optional):
       • Specifies the number of items per page.
       • Example: 10
     • displayment (Optional):
       • Specifies the maximum number of items to display.
       • Example: 20
     • groupBy (Optional):
       • Specifies the column to group by.
       • Example: 'columnName'

Execution:

1. Setting Up the Data Source:

   • Ensure that you've established a connection to the specified data source (database) before calling the displayAll method.

2. Calling the displayAll Method:

   • Once you've set the appropriate values for dataname and displayOptions, invoke the displayAll method.
   • The method sends a query to the database engine to retrieve the requested data.

3. Handling the Result:

   • The method returns a promise that resolves with an object containing the following properties:
     • acknowledged: A boolean indicating whether the operation was successful.
     • message: A success message.
     • results: An array of objects representing the retrieved data.

Example Usage:

Suppose we have a table named Employees with columns id, name, age, and department. We want to retrieve data with the following options:

• Apply a filter: age > 25
• Sort in descending order
• Display 10 items per page
• Group by the department column

Here's how you can use the displayAll method:

const dataname = 'your_data_source_name';
const displayOptions = {
  filters: { age: { $gt: 25 } },
  sortOrder: 'desc',
  pageSize: 10,
  groupBy: 'department'
};
 
// Call the displayAll method
db.displayAll(dataname, displayOptions)
  .then((result) => {
    if (result.acknowledged) {
      console.log(result.message); // Log success message
      console.log('Retrieved data:', result.results); // Log the retrieved data
    } else {
      console.error(result.errorMessage); // Log error message
    }
  })
  .catch((error) => {
    console.error('An error occurred:', error); // Catch any unexpected errors
  });

Notes:

• Adjust the displayOptions according to your specific requirements.
• Handle any errors by catching exceptions using .catch().