BTRV Edition User's Guide

name

A string value representing the field name. This will be the field name used by the SQL engine.

size

The number of bytes composing the field.

type

A string defining the data type containing. Please refer to the type mapping table.

scale{numeric attributes}

Used only by numerical field types, specifies the scale of the numeric values.

digits{numeric attributes}

Used only by numerical field types, specifies the number of digits of the numeric values.

dbtype{date attributes}{Boolean attributes}

Used to force the SQL type to DATE, DATETIME or BIT. The admitted values are:

"date" mapping into DATE or DATETIME depending on format attribute.

"boolean" mapping into BIT. At least one of cbtrue or cbfalse attributes must be specified.

format{date attributes}

Only for date types. Used to describe how the date will be written into the data file.

COBOL Only: Use the date-format-string used in $XFD.

hidden{optional attributes}

Normally used for the filler fields. Instructs the SQL engine to hide the current field.

bindefault{optional attributes}

bindefault is only used if defaultvalue and cbdefault are not specified.

bindefault specifies the binary value to write to disk when writing a record with null values from SQL.

This option provides more flexibility than cbdefault because it is binary instead of a string.

This value can either be specified as a hexadecimal string filling the entire buffer (e.g., bindefault="\x00\x01") or it can be one of the following predefined values:

low-value - Fills the field with COBOL LOW-VALUE.

high-value - Fills the field with COBOL HIGH-VALUE.

all-spaces - Fills the field with space characters.

For example, to fill the field with the COBOL LOW-VALUE: bindefault="low-value"

When using the hexadecimal string it is possible to specify multiple occurrences of the same byte using \x[#of occurrences]00

For example, for 12 occurrences of \x20 (space): bindefault="\x[12]20"

When OnConvertError (see below) is set to “error”, the error is propagated to SQ. The query fails unless the field content matches the bindefault, in which case the value will be exposed in SQL as NULL.

COBOL Only: For more details, see SQL/COBOL Data Conversion.

cbdefault{optional attributes}

cbdefault overrides bindefault. It is overridden by defaultvalue (use only one of these three).

cbdefault specifies the value to write to disk when writing a record with NULL values from SQL.

This value is the logical value to assign to the field (as a programmer would write it in a COBOL program). It is always specified as a string in the XDD file (use bindefault if a binary value is required). The SQL engine converts it into the proper representation for the field type before using it. For example, in the case of a PIC 9(4) COMP‑6, which indicates a 4-digit number stored in 2 bytes as an unsigned packed, a cbdefault="15" will be interpreted as a COMP‑6 representing the number 15 (\x00\x15 in hex).

When OnConvertError (see below) is set to “error”, the error is propagated to SQ. The query fails unless the field content matches the cbdefault, in which case the value will be exposed in SQL as NULL.

COBOL Only: For more details see SQL/COBOL Data Conversion.

defaultvalue{optional attributes}

If specified, takes precedence over bindefault and cbdefault.

Specifies the default value for new fields. Can be specified in one of the following formats:

• Hexadecimal string: value is prefixed with ‘\h'. For example: <field defaultvalue="\hA0B1C3D4"/>
• Hexadecimal elements: each value element is prefixed with ‘\x'. For example: <field defaultvalue="\xA0\xB1\xC3\xD4"/>. Multiple occurrences of the same element can be specified within sqare brackets. For example, 12 occurrences of space character: <field default="\x20[12]"/>
• Base64 string: value is prefixed with ‘\6’. For example: <field defaultvalue="MDAwMA=="/>
• COBOL Figurative Constant Values: accepted values are: “LOW-VALUE”, “LOW-VALUES”, “HIGH-VALUE”, “HIGH-VALUES”, “SPACE”, “SPACES”, “ALL-SPACES”. For example: <field defaultvalue="LOW-VALUE"/>
• Character string: value is not prefixed. For example: <field defaultvalue="0"/>

NOTE: To specify a character string that starts with backslash, prefix it with another backslash: <field defaultvalue="\\000"/>

onConvertError{optional attributes}

Specifies the action to take when this field value cannot be converted into SQL readable data.

If "error" is specified an error will be returned and the selected table records will not be shown unless the field content matches the bindefault or cbdefault in which case the value will be replaced with a SQL null value.

If "null" is specified the values that cannot be converted will be replaced with SQL null values.

If "strict" is specified an error will be returned and the selected table records will not be shown.

If "value:?" (where ? is the wanted value in SQL) is specified the value that cannot be converted will be replaced with the specified value

onSignError{optional attributes}

Used to force the sign of the field value in case it cannot be converted from the data on disk. The admitted values are:

"+" Forces to positive sign

"-" Forces to negative sign

cbtrue{optional attributes}

The value used in a Btrieve program that matches the BIT value 1 in SQL.

cbfalse{optional attributes}

The value used in a Btrieve program that matches the BIT value 1 in SQL.

julianBase{date}

Only for date types. Used to set the base date for Julian dates. The Julian date base must be specified using the YYYYMMDD format. It defaults to 17000301 (March 1st, 1700).