SQL Transformer

Useful transformers to be used with Dart's streams when reading SQL files.

At the time of this writing, there are only two available SQL transformers

SqlSplitterTransformer. Splits a stream of SQL statements into a stream of individual SQL statements.
SqlValuesTransformer. Replaces all values in a stream of SQL statements with a question mark.

Usage

Replacing / setting values to variables in SQL files

To do this, you must use the SqlValuesTransformer class, and pass as an argument a map with the values you'd like to replace.

For using and replacing variables with the transformer, you must use the SqlValuesTransformer class, and pass as an argument a map with the values you'd like to replace. For this to work, you must use the colon in front of the variable name in the SQL file.

Example SQL file:

select * from users where name = :name and last_name = :last_name;

Example Dart code:


import 'dart:convert';
import 'dart:io';

import 'package:sql_transformer/sql_transformer.dart';

void main(List<String> args) async {
  final file = File('get_users_and_purchases.sql');
  // The values you'd like to replace in the SQL file.
  final values = {'name': 'John', 'last_name': 'Doe'};

  final lines = utf8.decoder
      .bind(file.openRead())
      .transform(const SqlValuesTransformer(values));
  }

Splitting SQL file into individual SQL statements

import 'dart:convert';
import 'dart:io';

import 'package:sql_transformer/sql_transformer.dart';

void main(List<String> args) async {
  var file = File('get_users_and_purchases.sql');
  var lines = utf8.decoder
      .bind(file.openRead())
      .transform(const SqlSplitterTransformer());
}

You can also chain the transformers together

import 'dart:convert';
import 'dart:io';

import 'package:sql_transformer/sql_transformer.dart';

void main(List<String> args) async {
  var file = File('example.sql');
  var lines = utf8.decoder
      .bind(file.openRead())
      .transform(const SqlSplitterTransformer())
      .transform(const SqlValuesTransformer({'name': 'John', 'last_name': 'Doe'}));
}

License

BSD 3-Clause License (see LICENSE file)