COPY STRUCTURE EXTENDED

COPY STRUCTURE EXTENDED

Copy current database structure into a definition file

Syntax

      COPY STRUCTURE EXTENDED TO <xcFileName>

Arguments

<xcFileName> The name of the target definition file to create. (.dbf) is the default extension if none is given. It can be specified as a literal file name or as a character expression enclosed in parentheses.

Description

COPY STRUCTURE EXTENDED 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.

Examples

      // Open a database, then copy its structure to a new file,
      // Open the new file and list all its records
      USE Test
      COPY STRUCTURE EXTENDED TO TestStru
      USE TestStru
      LIST

Compliance

Clipper

Platforms

All

Seealso

COPY STRUCTURE, CREATE, CREATE FROM, DBCREATE(), DBSTRUCT(), __dbCopyStruct(), __dbCopyXStruct(), __dbCreate()

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2 responses to “COPY STRUCTURE EXTENDED

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