Caché ObjectScript Reference - InterSystems Documentation

parameters can only be set with the OPEN command; for sequential files some parameterscan only be set with the USE command. USE parameters are specific to the type of devicethat is being selected and to the particular implementation. The USE command keywordparameters are listed by device type in I/O Devices and Commands in the Caché I/O DeviceGuide.If you do not specify a list of USE parameters, Caché uses the device's default OPENparameters. The default parameters for a device are configurable. Go to the System ManagementPortal, select System Configuration, select Advanced Settings, on the pull-down Categorylist select Devices. Click “contents” to display the current list of devices. For the desireddevice, click “edit” to display its Open Parameter: option. Specify this value in the sameway you specify the OPEN command parameters, including the enclosing parentheses. Forexample, ("AVL":0:2048).Positional ParametersPositional parameters must be specified in a fixed sequence in the parameter list. You canomit a positional parameter (and receive the default value), but you must retain the colon toindicate the position of the omitted positional parameter. Trailing colons are not required;excess colons are ignored. The individual parameters and their positions are highly devicedependent.There are two types of positional parameters: values and letter code strings.A value can be an integer (for example, record size), a string (for example, host name), or avariable or expression that evaluates to a value.A letter code string uses individual letters to specify device characteristics for the openoperation. For most devices, this letter code string is one of the positional parameters. Youcan specify any number of letters in the string, and specify the letters in any order. Lettercodes are not case sensitive. A letter code string is enclosed in quotation marks; no spacesor other punctuation is allowed within a letter code string (exception: K and Y may be followedby a name delimited by backslashes: thus: K\name\). For example, when opening a sequentialfile, you might specify a letter code string of “ANDFW” (append to existing file, create newfile, delete file, fix-length records, write access.) The position of the letter code stringparameter, and the meanings of individual letters is highly device-dependent.Keyword ParametersUSEKeyword parameters can be specified in any sequence in the parameter list. A parameter listcan consist entirely of keyword parameters, or it can contain a mix of positional and keywordparameters. (Commonly, the positional parameters are specified first (in their correct positions)followed by the keyword parameters.) You must separate all parameters (positional or key-Caché ObjectScript Reference 147