Records

Records are attribute: value pairs associated to a unique ID

Syntax

// A record with an attribute
[attribute]

// A record with an attribute of given value
[attribute: value]

// A record with N attributes of given values
[attribute1: value1, ... , attributeN: valueN]

// A record nested within another record
[attribute1: [attribute2: value]]

// Equates a record and a variable
r = [attribute ...]

// Accessing an attribute on a record
r.attribute

// Join two records
[attribute1: attribute2]
[attribute2]

Description

Records are the predominant datatype in Eve. Records are used in two ways:

1. In a search you supply a pattern of attributes to match records in a supplied database.
2. In a bind or commit, you supply a pattern of attributes to insert into a database.

[attribute] matches all records with the given attribute.

[attribute: value] matches all records with the given attribute bound to specified value.

[attribute > value] matches all records with the given attribute bound filtered on a value. The inequality > can be one of the inequality operators.

[attribute1: value1, ... , attributeN: valueN] is the general case for records. This matches all records with all of the given attributes filtered on the given values.

[attribute1: [attribute2: value]] nests a record within another record.

r = [attribute ...] equates a record to a variable r.

r.attribute accesses the value of attribute on variable r.

Examples

Match all records with a name, and bind a #div for each one.

search
  [name]

bind @browser
  [#div text: name]

Records can have multiple attributes

search
  [#student name grade school]
  
bind @browser
  [#div text: "{{name}} is in {{grade}}th grade at {{school}}"]

Join records by binding attributes from one record into another record. Equate records with variables. Access record attributes using dot notation.

search
  school = [#school name address]
  student = [#student school: name]

bind @browser
  [#div text: "{{student.name}} attends {{school.name}} at {{address}}"]

Records can be nested.

commit
  [name: "Jeremy" spouse: [name: "Wendy"]]

Dot notation can be composed for deep access to records

search
  Jeremy = [name: "Jeremy"]

bind @browser
  [#div text: "{{Jeremy.name}} is married to {{Jeremy.spouse.name}}"]

See Also

search | bind | commit | tags | databases | equality | inequality | joins