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Universal Data Access Components (UniDAC) is a universal database access component that provides direct access to multiple databases such as Delphi, C++Builder, Lazarus (and Free Pascal) for Windows, Mac OS X, iOS, Android, Linux and FreeBSD 64 and 32 bit. We've pooled our long-standing experience with this widget, providing unified database connectivity access (Oracle, Microsoft SQL, etc.). This means that you can easily switch between different databases in your projects, as well as create cross-database application interfaces.

This topic considers the basic stages of working with datasets and ways to improve performance at each stage.

connected

If your application frequently performs connect/disconnect operations, you can use pooling mode (TCustomDAConnection.Pooling = True) for additional performance. It greatly reduces the connection reopening time (hundreds of times). This usually happens in Web applications.

implementation

If your application executes the same query multiple times, you can use the TCustomDADataSet.Prepare method or set the TDADataSetOptions.AutoPrepare property to improve performance. For example, it can be enabled for detail datasets in Master/Detail relationships or update objects in TAUDATE SQL. The performance gain achieved in this way can range from a few percent to several times, depending on the situation.

To execute SQL statements, TUniSQL components are preferable to TUniQuery. It can add a few percentage points of performance gain.

If the TCustomDADataSet.Options. Strictly Update option is set to False, the RowAffected property is not evaluated and becomes equal to zero. This improves query execution performance, so if you need to execute many data-update statements at once and don't mind the number of rows affected, set this option to False.

navigation

The Locate function works faster when the dataset is sorted locally on key field fields. You can set the local dataset ordering using the indexFieldNames property. If the dataset contains a large number of rows, the performance gain can be significant.

Find fields work faster when the Find dataset is sorted locally by the Find key.

Setting the TDadatasetOptions.CacheCalcFields property improves performance when sorting and positioning locally on calculated and lookup fields. It is also useful when the computed field expression contains complex calculations.

Setting the TDADataSetOptions.LocalMasterDetail option can greatly improve performance by avoiding server requests for detailed refreshes. Setting the TDADataSetOptions.DetailDelay option is useful to avoid refreshing details when switching master dataset records frequently.

update

If the application updates the dataset in CachedUpdates mode, setting the TCustomDADataSet.Options.UpdateBatchSize option above 1 can improve performance by several hundred times by reducing the number of requests to the server.

You can also improve data sending performance slightly (by a few percentage points) by using Dataset.UpdateObject.ModifyObject, Dataset.UpdateObject, and so on. By setting the AutoPrepare property of these objects, you can get very little additional performance improvement.

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