Differences

This shows you the differences between two versions of the page.

--- transformations:exportdb [2021/02/12 06:58] – dmitry
+++ transformations:exportdb [2021/02/12 07:02] – dmitry
@@ Line 3: / Line 3: @@
 Exports the current dataset into the database table which name is specified either explicitly or using a [[:parameters|parameter]]. The table must already exist. If the table doesn't exist it can be created using the [[sqlcommand|Database command]] action prior to exporting data into it.
-Note that the operation effectively //appends// rows to existing ones. If you need to remove old data use the [[sqlcommand|Database command]] action. If you need to update rows, use the [[transformations:updatedb|Update database table]] action.
+Note that the operation effectively //appends// rows to the target table. If you need to remove old data use the [[sqlcommand|Database command]] action. If you need to update rows, use the [[transformations:updatedb|Update database table]] action.
 ===Performance===
-Under the hood, the exporting is performed using SQL INSERT statements by batches of 10 or 100 or 1000 rows. Exporting in bigger batches can be slightly faster on narrow tables (i.e. tables with few fields). For wide tables (i.e. tables with hundreds of fields) or when columns contain long strings use smaller batches.
+Under the hood, the exporting is performed using SQL INSERT statements by batches of 10, 100, 1'000, or 10'000 rows. Exporting in bigger batches can be faster and is recommended for narrow tables (i.e. tables with few fields). For wide tables (i.e. tables with hundreds of fields) or when columns contain long strings use smaller batches, otherwise an export statement may fail due to the SQL statement limit of the database driver.
 Some databases have a performance bottleneck for batches of SQL INSERT statements which may lead to slow performance (especially on wide tables). Consider using the [[transformations:bulkexportdb|Bulk export]] action or bulk load statements with the [[sqlcommand|Database command]] action when exporting more than 1 million rows at once.