Database Library Documentation

Table of contents

• Static Database Access
  • db.entry
  • EPICS Base Functions
  • db.registerDatabaseHook
  • db.record
  • db.list

Static Database Access

db.entry

db.entry ()

Creates a DBENTRY pointer which can be used with all implemented static database access functions. dbFreeEntry will be called on the pointer automatically when the entry is garbage collected.

EPICS Base Functions

The following list of static database access functions are implemented, largely unchanged from their C API. Naming conventions have been changed to drop the initial “db” prefix and for the next character to be lowercase; so, for example, dbGetFieldName would become the module function getFieldName.

Functions which would return a status code, like dbFindRecord, will instead return a boolean representing success or failure (true or false respectively). Where a DBENTRY pointer is required as a parameter, instead instances of the dbentry class will be used, created with the aforementioned db.entry function.

• getNRecordTypes
• findRecordType
• firstRecordType
• nextRecordType
• getRecordTypeName
• getNFields
• firstField
• nextField
• getFieldDbfType
• getFieldName
• getDefault
• getPrompt
• getPromptGroup
• putRecordAttribute
• getRecordAttribute
• getNAliases
• getNRecords
• findRecord
• firstRecord
• nextRecord
• getRecordName
• isAlias
• createRecord
• createAlias
• deleteRecord
• deleteAliases
• copyRecord
• findField
• foundField
• getString
• putString
• isDefaultValue
• getNMenuChoices
• getMenuIndex
• putMenuIndex
• getMenuStringFromIndex
• getMenuIndexFromString
• getNLinks
• getLinkField
• firstInfo
• nextInfo
• findInfo
• getInfoName
• getInfoString
• putInfoString
• putInfo
• deleteInfo
• getInfo

db.registerDatabaseHook

db.registerDatabaseHook (dbhook)

Registers the provided function so that it is invoked each time the dbLoadRecords function is called by the IOC. The callback hook is invoked with two parameters; the first being the filepath to the database file being loaded, and the other being a table of the macro definitions provided to dbLoadRecords.

db.record

db.record ([recordtype,] recordname)

Creates an instance of the dbrecord class, a wrapper around record creation/access.

Returns a class instance with four instance methods, name, type, field, and info. ‘name’ and ‘type’ are accessor methods that will return the record name and the RTYP of the record.

‘field’ and ‘info’ are both functions that take in two strings as parameters, the first being a name and the second a value. ‘field’ attempts to find the record field with the given name and then calls dbPutString to set the value. While ‘info’ calls dbPutInfo to add a new info field with the given name and value to the record.

rec = db.record("stringin", "x:y:z")
rec:field("VAL", "test")
rec:info("autosave", "VAL")

The class instance itself can also be called as a function, taking in a dictionary of name-vale pairs. In doing so, the ‘field’ function is called for each pair, passing through the names and values to the function.

With lua syntactical sugar, you can chain together the record creation and the setting of fields like so:

db.record("ai", "x:y:z") {
    DTYP = "asynInt32",
    INP = "@asyn(A_PORT,0,1)PARAM_NAME"
}

db.list

db.list ()

Returns a list of all the PVs currently defined in the IOC. Each element of the list is a db.record instance.