Create structure extended file or use one to create new file
__dbCreate( <cFileName>, [<cFileFrom>], [<cRDDName>], ; [<lNew>], [<cAlias>] ) --> lUsed
<cFileName> is the target file name to create and then open. (.dbf) is the default extension if none is given.
<cFileFrom> is an optional structure extended file name from which the target file <cFileName> is going to be built. If omitted, a new empty structure extended file with the name <cFileName> is created and opened in the current work-area.
<cRDDName> is RDD name to create target with. If omitted, the default RDD is used.
<lNew> is an optional logical expression, (.T.) opens the target file name <cFileName> in the next available unused work-area and makes it the current work-area. (.F.) opens the target file in the current
work-area. Default value is (.F.). The value of <lNew> is ignored if <cFileFrom> is not specified.
<cAlias> is an optional alias to USE the target file with. If not specified, alias is based on the root name of <cFileName>.
__dbCreate() returns (.T.) if there is database USED in the current work-area (this might be the newly selected work-area), or (.F.) if there is no database USED. Note that on success a (.T.) would be returned, but on failure you probably end up with a run-time error and not a (.F.) value.
__dbCreate() works in two modes depending on the value of <cFileFrom>:
1) If <cFileFrom> is empty or not specified a new empty structure extended file with the name <cFileName> is created and then opened in the current work-area (<lNew> is ignored). The new
file has the following structure:
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
The CREATE command is preprocessed into the __dbCopyStruct() function during compile time and uses this mode.
2) If <cFileFrom> is specified, it is opened and assumed to be a structure extended file where each record contains at least the following fields (in no particular order): FIELD_NAME, FIELD_TYPE,
FIELD_LEN and FIELD_DEC. Any other field is ignored. From this information the file <cFileName> is then created and opened in the current or new work-area (according to <lNew>), if this is a new work-area it becomes the current.
For prehistoric compatibility reasons, structure extended file Character fields which are longer than 255 characters should be treated in a special way by writing part of the length in the FIELD_DEC according to the following formula:
FIELD->FIELD_DEC := Int( nLength / 256 ) FIELD->FIELD_LEN := ( nLength % 256 )
CREATE FROM command is preprocessed into __dbCopyStruct() function during compile time and use this mode.
// CREATE a new structure extended file, append some records and // then CREATE FROM this file a new database file __dbCreate( "template" ) dbAppend() FIELD->FIELD_NAME := "CHANNEL" FIELD->FIELD_TYPE := "N" FIELD->FIELD_LEN := 2 FIELD->FIELD_DEC := 0 dbAppend() FIELD->FIELD_NAME := "PROGRAM" FIELD->FIELD_TYPE := "C" FIELD->FIELD_LEN := 20 FIELD->FIELD_DEC := 0 dbAppend() FIELD->FIELD_NAME := "REVIEW" FIELD->FIELD_TYPE := "C" // this field is 1000 char long FIELD->FIELD_LEN := 232 // 1000 % 256 = 232 FIELD->FIELD_DEC := 3 // 1000 / 256 = 3 dbCloseArea() __dbCreate( "TV_Guide", "template" )
Library is rdd
COPY STRUCTURE, COPY STRUCTURE EXTENDED, CREATE, CREATE FROM, dbCreate(), dbStruct(), __dbCopyStruct(), __dbCopyXStruct()