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Hi Admin,
I am your China Site user.
Could you please help me a favor to learn more about the type: TDataValueVersionEh ?
I want to learn deep about the each value in type TDataValueVersionEh but found nothing in doc path.

or give me some advice on it.

Thanks.


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TDataValueVersionEh = (dvvOldValueEh, dvvCurValueEh, dvvEditValueEh, dvvValueEh, dvvOldestValue, dvvRefreshValue);

property DataValues[const FieldNames: string; DataValueVersion: TDataValueVersionEh]: Variant read GetDataValues write SetDataValues;

Hello

Here is a brief description of the TDataValueVersionEh type.

TDataValueVersionEh type defines the "version" or the type of value that should be returned or assigned. In most cases, the value dvvValueEh can be used, which defines the current active version of the field value.

In certain cases, the record can contain multiple values for the same field, but the active value is always only one version, which can be get or put by passing dvvValueEh value as a DataValueVersion parameter.
Multiple values appear when the record is edited or Post method is called for record that was received from a server.
Version values can be associated with the kinds of record value buffers. Three buffers can exist for one record:

1. Buffer of current values. This buffer is created when the record fetches data from a server.
2. Buffer of editing values. This buffer is created at the moment when the record changes it state to Editing. Buffer is destroyed when Post or Cancel method is called.
3. Buffer of old (server) record values. This buffer is created after the Post method is called if the record obtained it initial values from the server. Ones it is written in the buffer veluse doesn’t been changed hereafter. This buffer is used to generate «UPDATE» or «DELETE» SQL statements.

Unconditional versions - are versions that return values from a specific record buffer.
dvvCurValueEh – A value from a buffer of current values.
dvvEditValueEh – A value from a buffer of editing values.
dvvOldValueEh – A value from a buffer of old (server) record values.

Conditional versions - these are versions that return the value of the specified buffer, depending on the current state of the record:
dvvValueEh – If the record is in the Editing and Inserting state, then value from the buffer of editing values is returned, otherwise it takes values from the buffer of current values.
dvvOldestValue – If a buffer of old values exist then a value from this buffer is returned, else if a buffer of a current values exist then a value from this buffer is returned, otherwise, it returns a value from a buffer of editing values.
dvvRefreshValue – If a buffer of old values exist then a value from this buffer is returned, otherwise a value from a buffer of current values is returned.

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Best regards
Admin