__dbCopyXStruct()

Copy current database structure into a definition file

Syntax

__dbCopyXStruct( <cFileName> ) --> lSuccess

Arguments

<cFileName> is the name of target definition file to create. (.dbf) is the default extension if none is given.

Returns

__dbCopyXStruct() return (.F.) if no database is USED in the current work-area, (.T.) on success, or a run-time error if the file create operation had failed.

Description

__dbCopyXStruct() create a new database named <cFileName> with a pre-defined structure (also called "structure extended file"):

Field name	Type	Length	Decimals
FIELD_NAME	C	10	0
FIELD_TYPE	C	1	0
FIELD_LEN	N	3	0
FIELD_DEC	N	3	0

Each record in the new file contains information about one field in the original file. CREATE FROM could be used to create a database from the structure extended file.

For prehistoric compatibility reasons, Character fields which are longer than 255 characters are treated in a special way by writing part of the length in the FIELD_DEC according to the following formula (this is done internally):

FIELD->FIELD_DEC := int( nLength / 256 ) FIELD->FIELD_LEN := ( nLength % 256 )

Later if you want to calculate the length of a field you can use the following formula:

nLength := IIF( FIELD->FIELD_TYPE == "C", ; FIELD->FIELD_DEC * 256 + FIELD->FIELD_LEN, ; FIELD->FIELD_LEN )

COPY STRUCTURE EXTENDED command is preprocessed into __dbCopyXStruct() function during compile time.

      // Open a database, then copy its structure to a new file,
      // Open the new file and list all its records
      USE Test
      __dbCopyXStruct( "TestStru" )
      USE TestStru
      LIST

Status

Ready

Compliance

__dbCopyXStruct() works exactly like CA-Clipper's __dbCopyXStruct()

Platforms

All

Files

Library is rdd

See Also

• COPY STRUCTURE
• COPY STRUCTURE EXTENDED
• CREATE
• CREATE FROM
• DBCREATE()
• DBSTRUCT()
• __dbCopyStruct()
• __dbCreate()