step6

src/index.js

@@ -1,28 +1,13 @@
 // src/index.js
-
-const parseQuery = require('./queryParser');
-const readCSV = require('./csvReader');
-
-async function executeSELECTQuery(query) {
-    const { fields, table, whereClause } = parseQuery(query);
-    const data = await readCSV(`${table}.csv`);
-
-    // Filtering based on WHERE clause
-    const filteredData = whereClause
-        ? data.filter(row => {
-            const [field, value] = whereClause.split('=').map(s => s.trim());
-            return row[field] === value;
-        })
-        : data;
-
-    // Selecting the specified fields
-    return filteredData.map(row => {
-        const selectedRow = {};
-        fields.forEach(field => {
-            selectedRow[field] = row[field];
-        });
-        return selectedRow;
-    });
-}
-
-module.exports = executeSELECTQuery;
+function evaluateCondition(row, clause) {
+    const { field, operator, value } = clause;
+    switch (operator) {
+        case '=': return row[field] === value;
+        case '!=': return row[field] !== value;
+        case '>': return row[field] > value;
+        case '<': return row[field] < value;
+        case '>=': return row[field] >= value;
+        case '<=': return row[field] <= value;
+        default: throw new Error(`Unsupported operator: ${operator}`);
+    }
+}

src/queryParser.js

@@ -1,19 +1,12 @@
 // src/queryParser.js
-
-function parseQuery(query) {
-    const selectRegex = /SELECT (.+?) FROM (.+?)(?: WHERE (.*))?$/i;
-    const match = query.match(selectRegex);
-
-    if (match) {
-        const [, fields, table, whereClause] = match;
-        return {
-            fields: fields.split(',').map(field => field.trim()),
-            table: table.trim(),
-            whereClause: whereClause ? whereClause.trim() : null
-        };
-    } else {
-        throw new Error('Invalid query format');
-    }
-}
-
-module.exports = parseQuery;
+function parseWhereClause(whereString) {
+    const conditionRegex = /(.*?)(=|!=|>|<|>=|<=)(.*)/;
+    return whereString.split(/ AND | OR /i).map(conditionString => {
+        const match = conditionString.match(conditionRegex);
+        if (match) {
+            const [, field, operator, value] = match;
+            return { field: field.trim(), operator, value: value.trim() };
+        }
+        throw new Error('Invalid WHERE clause format');
+    });
+}

tests/step-07/index.test.js

@@ -90,4 +90,4 @@ test('Execute SQL Query with Not Equal to', async () => {
     const result = await executeSELECTQuery(queryWithGT);
     expect(result.length).toEqual(2);
     expect(result[0]).toHaveProperty('name');
-});
+});