JetGetDatabaseFileInfo Function

Artikkel
08/20/2021

Applies to: Windows | Windows Server

JetGetDatabaseFileInfo Function

The JetGetDatabaseFileInfo function retrieves various types of information about the database. This API can be called while a database is attached or online (with JetGetDatabaseInfo) or while the database or database engine is offline (with JetGetDatabaseFileInfo).

    JET_ERR JET_API JetGetDatabaseFileInfo(
      __in          const tchar* szDatabaseName,
      __out         void* pvResult,
      __in          unsigned long cbMax,
      __in          unsigned long InfoLevel
    );

Parameters

szDatabaseName

The path of the database from which to retrieve the information.

pvResult

Pointer to a buffer that will receive the specified information. The size of the buffer, in bytes, is passed in cbMax.

If this function fails, the contents of pvResult are undefined.

The information stored in pvResult depends on InfoLevel.

cbMax

The size, in bytes, of the buffer passed in pvResult.

InfoLevel

InfoLevel specifies which type of information should be retrieved about the specified database. It affects how pvResult is interpreted. Some InfoLevel objects are available only in the offline (JetGetDatabaseFileInfo) or online (JetGetDatabaseInfo) version of the API.

If the pvResult buffer provided is too small, either JET_errInvalidBufferSize or JET_errBufferTooSmall will be returned, depending on the InfoLevel.

JET_DbInfoFilesize

pvResult will be interpreted as a QWORD (8 bytes). Returns the size of the database in bytes.

JET_DbInfoUpgrade

pvResult will be interpreted as a JET_DBINFOUPGRADE. The JET_DBINFOUPGRADE structure will be populated with information pertaining to the specified database.

JET_DbInfoMisc

pvResult will be interpreted as a JET_DBINFOMISC. The JET_DBINFOMISC structure will be populated with information pertaining to the specified database.

JET_DbInfoDBInUse

pvResult will be interpreted as a BOOL (4 bytes). This will return whether the database engine currently has any open or attached databases.

Windows XP: This value is introduced in Windows XP.

JET_DbInfoPageSize

pvResult will be interpreted as an unsigned long. This will return the page size of the database in bytes.

Windows XP: This value is introduced in Windows XP.

JET_DbInfoCp

These InfoLevels are not yet supported and return default values. Do not use these InfoLevels.

JET_DbInfoCountry

These InfoLevels are not yet supported and return default values. Do not use these InfoLevels.

JET_DbInfoCollate

Same as JET_DbInfoCp.

JET_DbInfoIsam

These InfoLevels are deprecated and are not currently supported. Do not use these InfoLevels.

JET_DbInfoConnect

Same as JET_DbInfoIsam.

JET_DbInfoFileType

Windows Vista: This InfoLevel value is introduced in Windows Vista.

pvResult will be treated as a pointer to a DWORD. Returns an enumeration value, indicating what kind of file the engine considers this to be. File types are listed in the following table. For more information about these types of files and their usage to the engine, see Extensible Storage Engine Files.

Value	Meaning
JET_filetypeUnknown	The type of file is unknown, or not an ESE file type.
JET_filetypeDatabase	The file is a database file.
JET_filetypeLog	The file is a transaction log file.
JET_filetypeCheckpoint	The file is a checkpoint file.
JET_filetypeTempDatabase	The file is a temporary database file.

Return Value

This function returns the JET_ERR datatype with one of the following return codes. For more information about the possible ESE errors, see Extensible Storage Engine Errors and Error Handling Parameters.

Return code	Description
JET_errSuccess	The operation completed successfully.
JET_errFeatureNotAvailable	The InfoLevel requested was JET_DbInfoIsam. This is not supported.
JET_errBufferTooSmall	The buffer that is given in cbMax is too small for the desired information.
JET_errInvalidBufferSize	The buffer that is given in cbMax is not the correct size for the desired information.
JET_errInvalidParameter	One of the parameters that was provided contained an unexpected value, or the combination of several parameter values yielded an unexpected result. This error will be returned by JetGetDatabaseInfo when the DBID provided is not a valid (attached) database. This error will be returned by JetGetDatabaseFileInfo and JetGetDatabaseInfo when an InfoLevel requested is not supported by that version of the function.

If this function succeeds, the requested data will be returned in the output buffer.

If this function fails, the output buffer will be in an undefined state.

Requirements

Client	Requires Windows Vista, Windows XP, or Windows 2000 Professional.
Server	Requires Windows Server 2008, Windows Server 2003, or Windows 2000 Server.
Header	Declared in Esent.h.
Library	Use ESENT.lib.
DLL	Requires ESENT.dll.
Unicode	Implemented as JetGetDatabaseFileInfoW (Unicode) and JetGetDatabaseFileInfoA (ANSI).

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JetGetDatabaseFileInfo Function