A model of a schema with helpful methods for working with the schema and supported data.
Schema instances can be initialized with a schema source as a url to a JSON file or a JSON object.
The schema is initially validated (see validate).
By default validation errors will be stored in $errors but in a strict mode it will be instantly raised.
# Schema.load(descriptor, strict=FALSE)
R6Class object.
Object of R6Class .
Schema$new(descriptor = descriptor, strict = strict)Use Schema.load to instantiate Schema class.
getField(name)Get schema field by name.
name String with schema field name.
(Field/NULL) Returns Field instance or NULL if not found.
addField(descriptor)Add new field to schema. The schema descriptor will be validated with newly added field descriptor.
descriptor List of field descriptor.
TableSchemaError Raises any error occured in the process.
(Field/NULL) Returns added Field instance or NULL if not added.
removeField(name)Remove field resource by name. The schema descriptor will be validated after field descriptor removal.
name String with schema field name.
TableSchemaError Raises any error occured in the process.
(Field/NULL) Returns removed Field instances or NULL if not found.
castRow(row)Cast row based on field types and formats.
row Data row as a list of values.
(any) Returns cast data row.
infer(rows, headers=1)Cast row based on field types and formats.
rows List of lists representing rows.
headers data sample headers, one of:
row number containing headers (rows should contain headers rows)
list of headers (rows should NOT contain headers rows)
{Object} Returns Table Schema descriptor.
commit(strict)Cast row based on field types and formats.
strict Boolean, alter strict mode for further work.
TableSchemaError Raises any error occured in the process.
(Boolean) Returns TRUE on success and FALSE if not modified.
save(target)Cast row based on field types and formats.
target String, path where to save a descriptor.
TableSchemaError Raises any error occured in the process.
(Boolean) Returns TRUE on success.
validReturns validation status. It always TRUE in strict mode.
errorsReturns validation errors. It always empty in strict mode.
descriptorReturns list of schema descriptor.
primaryKeyReturns string list of schema primary key.
foreignKeysReturns list of schema foreign keys.
fieldsReturns list of Field instances.
fieldNamesReturns a list of field names.
The key words MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT,
SHOULD, SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL
in this package documents are to be interpreted as described in RFC 2119.
new()Schema$new(descriptor = "{}", strict = FALSE, caseInsensitiveHeaders = FALSE)descriptorschema descriptor, a JSON string, URL or file
strictflag to alter validation behaviour:
if FALSE error will not be raised and all error will be collected in schema$errors
if TRUE any validation error will be raised immediately
getField()Schema$getField(fieldName, index = 1)
addField()Schema$addField(descriptor)
descriptorschema descriptor, a JSON string, URL or file
removeField()Schema$removeField(name)
castRow()Schema$castRow(items, failFast = FALSE, skipConstraints = FALSE)
infer()Schema$infer(rows, headers = 1)
commit()Schema$commit(strict = NULL)
strictflag to alter validation behaviour:
if FALSE error will not be raised and all error will be collected in schema$errors
if TRUE any validation error will be raised immediately
save()Schema$save(target)
clone()The objects of this class are cloneable with this method.
Schema$clone(deep = FALSE)
deepWhether to make a deep clone.