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FireDAC.Stan.Option.TFDFetchOptions.Items

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Delphi

property Items: TFDFetchItems read GetItems write SetItems  stored IsIS default [fiBlobs, fiDetails, fiMeta];

C++

__property TFDFetchItems Items = {read=GetItems, write=SetItems, stored=IsIS, default=7};

Properties

Type Visibility Source Unit Parent
property published
FireDAC.Stan.Option.pas
FireDAC.Stan.Option.hpp
FireDAC.Stan.Option TFDFetchOptions

Description

Controls what kind of data to fetch.

Use the Items property to control which types of data and metadata to fetch.

Option 

Description 

fiBlobs

If included, then the BLOB field values are fetched together with other record fields. Otherwise, the fetching is deferred until a BLOB value is really read.

Note: Excluding fiBlobs from Items does not modify the SELECT list of an SQL command. If a DBMS transfers BLOB values by value (eg, Oracle LONG, MySQL, SQL Server, SQLite), then, in any case, the BLOB values will be delivered to the client, not to the network. But they will not be stored in the client records cache. But if a DBMS transfers BLOB values by reference (eg, Oracle CLOB / BLOB, InterBase, Firebird), then the BLOB values will not be delivered or stored.

fiDetails

If included, then the nested cursor fields are fetched together with other record fields. Otherwise, the fetching is deferred until a nested cursor value is really read. 

fiMeta

If included, then the command metadata is fetched. Otherwise, the programmer must supply metadata on his own. The kind of metadata and the point when it will be fetched depend on the command kind:

  • TFDCustomStoredProc, CommandKind = ckStoredProc, etc. The metadata is the description of the stored procedure parameters. It will be fetched at Prepare call. If fiMeta is not in Items, then the programmer must fill the Params collection himself.
  • TFDCustomQuery, CommandKind = ckSelect, etc. The metadata is the set of the base table columns, forming the table primary key. It is used to automatically generate the updating of SQL commands. The metadata will be fetched at Open/Define calls. If fiMeta is not in Items, then the programmer must do one of following to specify the PK fields:
  • Include pfInKey in ProviderFlags for PK fields.
  • Set KeyFields to the colon separated list of PK field names.
  • Include coInKey in TFDDatSColumn.Options for PK columns.

 

The default value is [fiBlobs, fiDetails, fiMeta], meaning that all data and metadata will be fetched automatically at proper moments.

See Also

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