feat(sync): allow altering comments (#10758)

lib/dialects/mssql/query-generator.js

@@ -265,10 +265,18 @@ class MSSQLQueryGenerator extends AbstractQueryGenerator {
   changeColumnQuery(tableName, attributes) {
     const attrString = [],
       constraintString = [];
+    let commentString = '';
 
     for (const attributeName in attributes) {
       const quotedAttrName = this.quoteIdentifier(attributeName);
-      const definition = attributes[attributeName];
+      let definition = attributes[attributeName];
+      if (definition.includes('COMMENT ')) {
+        const commentMatch = definition.match(/^(.+) (COMMENT.*)$/);
+        const commentText = commentMatch[2].replace('COMMENT', '').trim();
+        commentString += this.commentTemplate(commentText, tableName, attributeName);
+        // remove comment related substring from dataType
+        definition = commentMatch[1];
+      }
       if (definition.includes('REFERENCES')) {
         constraintString.push(`FOREIGN KEY (${quotedAttrName}) ${definition.replace(/.+?(?=REFERENCES)/, '')}`);
       } else {
@@ -285,7 +293,7 @@ class MSSQLQueryGenerator extends AbstractQueryGenerator {
       finalQuery += `ADD ${constraintString.join(', ')}`;
     }
 
-    return `ALTER TABLE ${this.quoteTable(tableName)} ${finalQuery};`;
+    return `ALTER TABLE ${this.quoteTable(tableName)} ${finalQuery};${commentString}`;
   }
 
   renameColumnQuery(tableName, attrBefore, attributes) {

lib/dialects/postgres/query-generator.js

@@ -268,7 +268,6 @@ class PostgresQueryGenerator extends AbstractQueryGenerator {
   changeColumnQuery(tableName, attributes) {
     const query = subQuery => `ALTER TABLE ${this.quoteTable(tableName)} ALTER COLUMN ${subQuery};`;
     const sql = [];
-
     for (const attributeName in attributes) {
       let definition = this.dataTypeMapping(tableName, attributeName, attributes[attributeName]);
       let attrSql = '';
@@ -536,11 +535,13 @@ class PostgresQueryGenerator extends AbstractQueryGenerator {
     }
 
     if (attribute.comment && typeof attribute.comment === 'string') {
-      if (options && options.context === 'addColumn') {
+      if (options && (options.context === 'addColumn' || options.context === 'changeColumn')) {
         const quotedAttr = this.quoteIdentifier(options.key);
         const escapedCommentText = this.escape(attribute.comment);
         sql += `; COMMENT ON COLUMN ${this.quoteTable(options.table)}.${quotedAttr} IS ${escapedCommentText}`;
       } else {
+        // for createTable event which does it's own parsing
+        // TODO: centralize creation of comment statements here
         sql += ` COMMENT ${attribute.comment}`;
       }
     }
@@ -575,7 +576,7 @@ class PostgresQueryGenerator extends AbstractQueryGenerator {
 
     for (const key in attributes) {
       const attribute = attributes[key];
-      result[attribute.field || key] = this.attributeToSQL(attribute, options);
+      result[attribute.field || key] = this.attributeToSQL(attribute, Object.assign({ key }, options || {}));
     }
 
     return result;

lib/query-interface.js

@@ -230,7 +230,7 @@ class QueryInterface {
       });
     }
 
-    attributes = this.QueryGenerator.attributesToSQL(attributes, { context: 'createTable' });
+    attributes = this.QueryGenerator.attributesToSQL(attributes, { table: tableName, context: 'createTable' });
     sql = this.QueryGenerator.createTableQuery(tableName, attributes, options);
 
     return promise.then(() => this.sequelize.query(sql, options));
@@ -567,7 +567,10 @@ class QueryInterface {
       // sqlite needs some special treatment as it cannot change a column
       return SQLiteQueryInterface.changeColumn(this, tableName, attributes, options);
     }
-    const query = this.QueryGenerator.attributesToSQL(attributes);
+    const query = this.QueryGenerator.attributesToSQL(attributes, { 
+      context: 'changeColumn',
+      table: tableName
+    });
     const sql = this.QueryGenerator.changeColumnQuery(tableName, query);
 
     return this.sequelize.query(sql, options);

test/integration/query-interface/changeColumn.test.js

@@ -220,6 +220,21 @@ describe(Support.getTestDialectTeaser('QueryInterface'), () => {
           });
         });
 
+        it('should change the comment of column', function() {
+          return this.queryInterface.describeTable({
+            tableName: 'users'
+          }).then(describedTable => {
+            expect(describedTable.level_id.comment).to.be.equal(null);
+            return this.queryInterface.changeColumn('users', 'level_id', {
+              type: DataTypes.INTEGER,
+              comment: 'FooBar'
+            });
+          }).then(() => {
+            return this.queryInterface.describeTable({ tableName: 'users' });
+          }).then(describedTable2 => {
+            expect(describedTable2.level_id.comment).to.be.equal('FooBar');
+          });
+        });
       });
     }
   });