mirror of https://github.com/AMT-Cheif/drift.git
80 lines
1.8 KiB
Dart
80 lines
1.8 KiB
Dart
import 'package:sqlparser/sqlparser.dart';
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// Example that parses a select statement on some tables defined below and
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// prints what columns would be returned by that statement.
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void main() {
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final engine = SqlEngine()
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..registerTable(frameworks)
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..registerTable(languages)
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..registerTable(frameworkToLanguage);
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final result = engine.analyze('''
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SELECT f.* FROM frameworks f
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INNER JOIN uses_language ul ON ul.framework = f.id
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INNER JOIN languages l ON l.id = ul.language
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WHERE l.name = 'Dart'
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ORDER BY f.name ASC, f.popularity DESC
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LIMIT 5 OFFSET 5 * 3
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''');
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result.errors.forEach(print);
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final select = result.root as SelectStatement;
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final columns = select.resolvedColumns;
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print('the query returns ${columns.length} columns');
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for (final column in columns) {
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final type = result.typeOf(column);
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print('${column.name}, which will be a $type');
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}
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}
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// declare some tables. I know this is verbose and boring, but it's needed so
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// that the analyzer knows what's going on.
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final Table frameworks = Table(
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name: 'frameworks',
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resolvedColumns: [
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TableColumn(
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'id',
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const ResolvedType(type: BasicType.int),
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),
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TableColumn(
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'name',
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const ResolvedType(type: BasicType.text),
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),
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TableColumn(
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'popularity',
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const ResolvedType(type: BasicType.real),
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),
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],
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);
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final Table languages = Table(
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name: 'languages',
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resolvedColumns: [
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TableColumn(
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'id',
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const ResolvedType(type: BasicType.int),
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),
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TableColumn(
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'name',
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const ResolvedType(type: BasicType.text),
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),
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],
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);
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final Table frameworkToLanguage = Table(
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name: 'uses_language',
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resolvedColumns: [
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TableColumn(
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'framework',
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const ResolvedType(type: BasicType.int),
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),
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TableColumn(
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'language',
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const ResolvedType(type: BasicType.int),
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),
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],
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);
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