From 6af3b7cf9818b7ae0f70d98f546cecc19bc84618 Mon Sep 17 00:00:00 2001
From: Muhammad Aaqil <aaqilcs102@gmail.com>
Date: Sun, 13 Oct 2024 23:17:13 +0500
Subject: [PATCH] feat: fetch index information for columns

Signed-off-by: Muhammad Aaqil <aaqilcs102@gmail.com>
---
 lib/discovery.js | 107 +++++++++++++++++++++++++++++++++++------------
 1 file changed, 80 insertions(+), 27 deletions(-)

diff --git a/lib/discovery.js b/lib/discovery.js
index 615c54da..6b764ef3 100644
--- a/lib/discovery.js
+++ b/lib/discovery.js
@@ -157,34 +157,87 @@ function mixinDiscovery(MySQL, mysql) {
   MySQL.prototype.buildQueryColumns = function(schema, table, options = {}) {
     let sql = null;
     if (schema) {
-      sql = paginateSQL('SELECT table_schema AS "owner",' +
-        ' table_name AS "tableName",' +
-        ' column_name AS "columnName",' +
-        ' data_type AS "dataType",' +
-        ' character_maximum_length AS "dataLength",' +
-        ' numeric_precision AS "dataPrecision",' +
-        ' numeric_scale AS "dataScale",' +
-        ' column_type AS "columnType",' +
-        ' is_nullable = \'YES\' AS "nullable",' +
-        ' CASE WHEN extra LIKE \'%auto_increment%\' THEN 1 ELSE 0 END AS "generated"' +
-        ' FROM information_schema.columns' +
-        ' WHERE table_schema=' + mysql.escape(schema) +
-        (table ? ' AND table_name=' + mysql.escape(table) : ''),
-      'table_name, ordinal_position', {});
+      sql = paginateSQL(
+        `SELECT 
+            c.table_schema AS "owner",
+            c.table_name AS "tableName",
+            c.column_name AS "columnName",
+            c.data_type AS "dataType",
+            c.character_maximum_length AS "dataLength",
+            c.numeric_precision AS "dataPrecision",
+            c.numeric_scale AS "dataScale",
+            c.column_type AS "columnType",
+            c.is_nullable = 'YES' AS "nullable",
+            CASE WHEN c.extra LIKE '%auto_increment%' THEN 1 ELSE 0 END AS "generated",
+            s.index_name AS "indexName",
+            s.non_unique AS "nonUnique",
+            s.seq_in_index AS "seqInIndex",
+            s.cardinality AS "cardinality",
+            s.index_type AS "indexType",
+            CASE WHEN fk.column_name IS NOT NULL THEN 1 ELSE 0 END AS "isForeignKey"  -- Flag for foreign key
+         FROM 
+            information_schema.columns c
+         LEFT JOIN 
+            information_schema.statistics s 
+         ON 
+            c.table_schema = s.table_schema 
+            AND c.table_name = s.table_name 
+            AND c.column_name = s.column_name
+         LEFT JOIN 
+            information_schema.KEY_COLUMN_USAGE fk 
+         ON 
+            c.table_schema = fk.table_schema 
+            AND c.table_name = fk.table_name 
+            AND c.column_name = fk.column_name 
+            AND fk.referenced_table_name IS NOT NULL  -- Ensure it's a foreign key
+         WHERE 
+            c.table_schema = ${mysql.escape(schema)} 
+            ${table ? ' AND c.table_name = ' + mysql.escape(table) : ''}
+        `,
+        'c.table_name, c.ordinal_position',
+        {},
+      );
     } else {
-      sql = paginateSQL('SELECT table_schema AS "owner",' +
-        ' table_name AS "tableName",' +
-        ' column_name AS "columnName",' +
-        ' data_type AS "dataType",' +
-        ' character_maximum_length AS "dataLength",' +
-        ' numeric_precision AS "dataPrecision",' +
-        ' numeric_scale AS "dataScale",' +
-        ' column_type AS "columnType",' +
-        ' is_nullable = \'YES\' AS "nullable",' +
-        ' CASE WHEN extra LIKE \'%auto_increment%\' THEN 1 ELSE 0 END AS "generated"' +
-        ' FROM information_schema.columns' +
-        (table ? ' WHERE table_name=' + mysql.escape(table) : ''),
-      'table_name, ordinal_position', {});
+      sql = paginateSQL(
+        `SELECT 
+            columns.table_schema AS "owner",
+            columns.table_name AS "tableName",
+            columns.column_name AS "columnName",
+            columns.data_type AS "dataType",
+            columns.character_maximum_length AS "dataLength",
+            columns.numeric_precision AS "dataPrecision",
+            columns.numeric_scale AS "dataScale",
+            columns.column_type AS "columnType",
+            columns.is_nullable = 'YES' AS "nullable",
+            CASE WHEN columns.extra LIKE '%auto_increment%' THEN 1 ELSE 0 END AS "generated",
+            indexes.index_name AS "indexName",
+            indexes.seq_in_index AS "indexColumnOrder",
+            indexes.non_unique AS "nonUnique",
+            indexes.cardinality AS "cardinality",      -- Cardinality of the index
+            indexes.index_type AS "indexType",         -- Type of the index
+            CASE WHEN fk.column_name IS NOT NULL THEN 1 ELSE 0 END AS "isForeignKey"  -- Flag for foreign key
+         FROM 
+            information_schema.columns AS columns
+         LEFT JOIN 
+            information_schema.statistics AS indexes 
+         ON 
+            columns.table_schema = indexes.table_schema 
+            AND columns.table_name = indexes.table_name 
+            AND columns.column_name = indexes.column_name
+         LEFT JOIN 
+            information_schema.KEY_COLUMN_USAGE AS fk 
+         ON 
+            columns.table_schema = fk.table_schema 
+            AND columns.table_name = fk.table_name 
+            AND columns.column_name = fk.column_name 
+            AND fk.referenced_table_name IS NOT NULL  -- Ensure it's a foreign key
+         WHERE 
+            columns.table_schema = ${mysql.escape(schema)} 
+            ${table ? ' AND columns.table_name = ' + mysql.escape(table) : ''}
+        `,
+        'columns.table_name, columns.ordinal_position',
+        {},
+      );
     }
     if (options.orderBy) {
       sql += ' ORDER BY ' + options.orderBy;