feat: fetch only base column info for modifications, drop columnComment only if exists

plugins/dbgate-plugin-mssql/src/backend/MsSqlAnalyser.js

@@ -90,7 +90,7 @@ function getColumnInfo({
 /**
  * @param {ReturnType<objectTypeToField>} fieldType
  * @param {any} item
- * @param {Array<ReturnType<getColumnInfo>>} columns
+ * @param {Array<{ objectId: string; columnComment: string }>} columns
  * @returns {string|null}
  */
 function createObjectContentHash(fieldType, item, columns) {
@@ -273,8 +273,8 @@ class MsSqlAnalyser extends DatabaseAnalyser {
 
   async _getFastSnapshot() {
     const modificationsQueryData = await this.analyserQuery('modifications');
-    const columnsRows = await this.analyserQuery('columns', ['tables']);
+    const baseColumnsRows = await this.analyserQuery('columns', ['tables']);
-    const columns = columnsRows.rows.map(getColumnInfo);
+    const baseColumns = baseColumnsRows.rows.map(getColumnInfo);
     const tableSizes = await this.analyserQuery('tableSizes');
 
     const res = DatabaseAnalyser.createEmptyStructure();
@@ -285,7 +285,7 @@ class MsSqlAnalyser extends DatabaseAnalyser {
 
       res[field].push({
         objectId,
-        contentHash: createObjectContentHash(field, item, columns),
+        contentHash: createObjectContentHash(field, item, baseColumns),
         schemaName,
         pureName,
       });

plugins/dbgate-plugin-mssql/src/backend/sql/baseColumns.js

@@ -0,0 +1,10 @@
+module.exports = `
+select c.object_id as objectId,
+	ep.value as columnComment
+from sys.columns c
+inner join sys.objects o on c.object_id = o.object_id
+INNER JOIN sys.schemas u ON u.schema_id=o.schema_id 
+left join sys.extended_properties ep on ep.major_id = c.object_id and ep.minor_id = c.column_id and ep.name = 'MS_Description'
+where o.type IN ('U', 'V') and o.object_id =OBJECT_ID_CONDITION and u.name =SCHEMA_NAME_CONDITION
+order by c.column_id
+`;

plugins/dbgate-plugin-mssql/src/backend/sql/index.js

@@ -13,6 +13,7 @@ const viewColumns = require('./viewColumns');
 const indexes = require('./indexes');
 const indexcols = require('./indexcols');
 const triggers = require('./triggers');
+const baseColumns = require('./baseColumns');
 
 module.exports = {
   columns,
@@ -30,4 +31,5 @@ module.exports = {
   indexcols,
   tableSizes,
   triggers,
+  baseColumns,
 };

plugins/dbgate-plugin-mssql/src/frontend/MsSqlDumper.js

@@ -168,21 +168,34 @@ class MsSqlDumper extends SqlDumper {
   changeColumnComment(oldcol, newcol) {
     if (oldcol.columnComment === newcol.columnComment) return;
 
-    if (oldcol.columnComment) this.dropColumnComment(newcol);
+    if (oldcol.columnComment) this.dropColumnCommentIfExists(newcol);
     if (newcol.columnComment) this.createColumnComment(newcol);
   }
 
   /**
    * @param {import('dbgate-types').ColumnInfo} column
    */
-  dropColumnComment(column) {
+  dropColumnCommentIfExists(column) {
     const { schemaName, columnName, pureName } = column;
+    const fullName = `${schemaName && schemaName + '.'}${pureName}`;
 
+    this.put('&>^if ^exists (&n');
+    this.put('&>^select 1 ^from sys.extended_properties&n');
+    this.put("^where major_id = OBJECT_ID('%s')&n", fullName);
+    this.put(
+      "^and minor_id = (^select column_id ^from sys.columns ^where object_id = OBJECT_ID('%s') ^and name = '%s')&n",
+      fullName,
+      columnName
+    );
+    this.put("^and name = N'MS_Description'&<&<&n");
+    this.put(')&n');
+    this.put('&>^begin&n');
     this.put('&>^exec sp_dropextendedproperty&n');
-    this.put("@name = N'MS_Description',");
+    this.put("@name = N'MS_Description',&n");
     this.put("@level0type = N'SCHEMA', @level0name = '%s',&n", schemaName);
     this.put("@level1type = N'TABLE',  @level1name = '%s',&n", pureName);
-    this.put("@level2type = N'COLUMN', @level2name = '%s'&<", columnName);
+    this.put("@level2type = N'COLUMN', @level2name = '%s'&<&n", columnName);
+    this.put('^end');
     this.endCommand();
   }