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Specifying a Batch Move Mode

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Note: The Borland Database Engine (BDE) has been deprecated, so it will not be enhanced. For instance, BDE will never have Unicode support. You should not undertake new development with BDE. Consider migrating your existing database applications from BDE to dbExpress.

The Mode property specifies the operation a batch move component performs:

Batch move modes

Property Purpose

batAppend

Append records to the destination table.

batUpdate

Update records in the destination table with matching records from the source table. Updating is based on the current index of the destination table.

batAppendUpdate

If a matching record exists in the destination table, update it. Otherwise, append records to the destination table.

batCopy

Create the destination table based on the structure of the source table. If the destination table already exists, it is dropped and recreated.

batDelete

Delete records in the destination table that match records in the source table.


Appending records

To append data, the destination dataset must represent an existing table. During the append operation, the BDE converts data to appropriate data types and sizes for the destination dataset, if necessary. If a conversion is not possible, an exception is thrown and the data is not appended.

Updating records

To update data, the destination dataset must represent an existing table and must have an index defined that enables records to be matched. If the primary index fields are used for matching, records with index fields in the destination dataset that match index fields records in the source dataset are overwritten with the source data. During the update operation, the BDE converts data to appropriate data types and sizes for the destination dataset, if necessary.

Appending and updating records

To append and update data, the destination dataset must represent an existing table and must have an index defined that enables records to be matched. If the primary index fields are used for matching, records with index fields in the destination dataset that match index fields records in the source dataset are overwritten with the source data. Otherwise, data from the source dataset is appended to the destination dataset. During append and update operations, the BDE converts data to appropriate data types and sizes for the destination dataset, if necessary.

Copying datasets

To copy a source dataset, the destination dataset should not represent an exist table. If it does, the batch move operation overwrites the existing table with a copy of the source dataset.

If the source and destination datasets are maintained by different types of database engines, for example, Paradox and InterBase, the BDE creates a destination dataset with a structure as close as possible to that of the source dataset and automatically performs data type and size conversions as necessary.

Note: TBatchMove does not copy metadata structures such as indexes, constraints, and stored procedures. You must recreate these metadata objects on your database server as appropriate.

Deleting records

To delete data in the destination dataset, it must represent an existing table and must have an index defined that enables records to be matched. If the primary index fields are used for matching, records with index fields in the destination dataset that match index fields records in the source dataset are deleted in the destination table.

See Also

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