Copyright © 2016 M/Gateway Developments Ltd
EWD 3 Training Course
Part 25
JavaScript Abstraction of Global Storage:
Global Storage as a
Document Database
Rob Tweed
Director, M/Gateway Developments Ltd
Twitter: @rtweed

Copyright © 2016 M/Gateway Developments Ltd
1-1 correspondence
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: {
e1: {
f1a: 'bar1a',
f2a: 'bar2a'
},
e2: {
f1b: 'bar1b',
f2b: 'bar2b',
f3b: 'bar3b'
}
}
}
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d","e1","f1a")="bar1a"
myDoc("d","e1","f2a")="bar2a"
myDoc("d","e2","f1b")="bar1b"
myDoc("d","e2","f2b")="bar2b"
myDoc("d","e2","f3b")="bar3b"
Global Storage
JavaScript Object

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DocumentNode methods for document database / JSON mapping:
getDocument()
setDocument()
Document Database Methods

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Instantiate a DocumentNode Object
var doc = new this.documentStore.DocumentNode('myDoc');
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d","e1","f1a")="bar1a"
myDoc("d","e1","f2a")="bar2a"
myDoc("d","e2","f1b")="bar1b"
myDoc("d","e2","f2b")="bar2b"
myDoc("d","e2","f3b")="bar3b"

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getDocument()
var doc = new this.documentStore.DocumentNode('myDoc');
var myObj = doc.getDocument();
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d","e1","f1a")="bar1a"
myDoc("d","e1","f2a")="bar2a"
myDoc("d","e2","f1b")="bar1b"
myDoc("d","e2","f2b")="bar2b"
myDoc("d","e2","f3b")="bar3b"
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: {
e1: {
f1a: 'bar1a',
f2a: 'bar2a'
},
e2: {
f1b: 'bar1b',
f2b: 'bar2b',
f3b: 'bar3b'
}
}
}
creates

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getDocument()
var doc = new this.documentStore.DocumentNode('myDoc');
var myObj = doc.getDocument();
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d","e1","f1a")="bar1a"
myDoc("d","e1","f2a")="bar2a"
myDoc("d","e2","f1b")="bar1b"
myDoc("d","e2","f2b")="bar2b"
myDoc("d","e2","f3b")="bar3b"
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: {
e1: {
f1a: 'bar1a',
f2a: 'bar2a'
},
e2: {
f1b: 'bar1b',
f2b: 'bar2b',
f3b: 'bar3b'
}
}
}
myObj is a standard in-memory JavaScript object
containing a copy of the data that was held within
the DocumentNode's sub-tree of nodes
creates

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setDocument()
var myObj = { // create the object shown to the right };
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: {
e1: {
f1a: 'bar1a',
f2a: 'bar2a'
},
e2: {
f1b: 'bar1b',
f2b: 'bar2b',
f3b: 'bar3b'
}
}
}

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setDocument()
var myObj = { // create the object shown to the right };
var doc = new this.documentStore.DocumentNode('myDoc');
// doesn't yet exist on disk myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: {
e1: {
f1a: 'bar1a',
f2a: 'bar2a'
},
e2: {
f1b: 'bar1b',
f2b: 'bar2b',
f3b: 'bar3b'
}
}
}

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setDocument()
var myObj = { // create the object shown to the right };
var doc = new this.documentStore.DocumentNode('myDoc');
doc.setDocument(myObj);
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d","e1","f1a")="bar1a"
myDoc("d","e1","f2a")="bar2a"
myDoc("d","e2","f1b")="bar1b"
myDoc("d","e2","f2b")="bar2b"
myDoc("d","e2","f3b")="bar3b"
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: {
e1: {
f1a: 'bar1a',
f2a: 'bar2a'
},
e2: {
f1b: 'bar1b',
f2b: 'bar2b',
f3b: 'bar3b'
}
}
}
creates

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setDocument()
var myObj = { // create the object shown to the right };
var doc = new this.documentStore.DocumentNode('myDoc');
doc.setDocument(myObj);
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d","e1","f1a")="bar1a"
myDoc("d","e1","f2a")="bar2a"
myDoc("d","e2","f1b")="bar1b"
myDoc("d","e2","f2b")="bar2b"
myDoc("d","e2","f3b")="bar3b"
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: {
e1: {
f1a: 'bar1a',
f2a: 'bar2a'
},
e2: {
f1b: 'bar1b',
f2b: 'bar2b',
f3b: 'bar3b'
}
}
}
myDoc is created on disk, containing a copy of
the data that was held within the myObj
object, now mapped to Global Storage nodes
creates

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Applicable for Any DocumentNode
These methods can be applied at any level within an on-disk Document
var dnode = new this.documentStore.DocumentNode('myDoc', ['d' ]);
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d","e1","f1a")="bar1a"
myDoc("d","e1","f2a")="bar2a"
myDoc("d","e2","f1b")="bar1b"
myDoc("d","e2","f2b")="bar2b"
myDoc("d","e2","f3b")="bar3b"

Copyright © 2016 M/Gateway Developments Ltd
Applicable for Any DocumentNode
These methods can be applied at any level within an on-disk Document
var dnode = new this.documentStore.DocumentNode('myDoc', ['d' ]);
var myObj = dnode.getDocument();
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d","e1","f1a")="bar1a"
myDoc("d","e1","f2a")="bar2a"
myDoc("d","e2","f1b")="bar1b"
myDoc("d","e2","f2b")="bar2b"
myDoc("d","e2","f3b")="bar3b"
myObj = {
e1: {
f1a: 'bar1a',
f2a: 'bar2a'
},
e2: {
f1b: 'bar1b',
f2b: 'bar2b',
f3b: 'bar3b'
}
}

Copyright © 2016 M/Gateway Developments Ltd
Applicable for Any DocumentNode
These methods can be applied at any level within an on-disk Document
var dnode = new this.documentStore.DocumentNode('myDoc', ['d' ]);
var myObj = dnode.getDocument();
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d","e1","f1a")="bar1a"
myDoc("d","e1","f2a")="bar2a"
myDoc("d","e2","f1b")="bar1b"
myDoc("d","e2","f2b")="bar2b"
myDoc("d","e2","f3b")="bar3b"
myObj = {
e1: {
f1a: 'bar1a',
f2a: 'bar2a'
},
e2: {
f1b: 'bar1b',
f2b: 'bar2b',
f3b: 'bar3b'
}
}
myObj is created from just the sub-tree
of Nodes under myDoc("d")

Copyright © 2016 M/Gateway Developments Ltd
Applicable for Any DocumentNode
These methods can be applied at any level within an on-disk Document
var dnode = new this.documentStore.DocumentNode('myDoc', ['d' ]);
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d","e1","f1a")="bar1a"
myDoc("d","e1","f2a")="bar2a"
myDoc("d","e2","f1b")="bar1b"
myDoc("d","e2","f2b")="bar2b"
myDoc("d","e2","f3b")="bar3b"

Copyright © 2016 M/Gateway Developments Ltd
Applicable for Any DocumentNode
These methods can be applied at any level within an on-disk Document
var dnode = new this.documentStore.DocumentNode('myDoc', ['d' ]);
var myObj = { // create the object shown to the right };
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d","e1","f1a")="bar1a"
myDoc("d","e1","f2a")="bar2a"
myDoc("d","e2","f1b")="bar1b"
myDoc("d","e2","f2b")="bar2b"
myDoc("d","e2","f3b")="bar3b"
myObj = {
g: 1000,
h2: {
w1: 'foo',
w2: 'bar'
}
}

Copyright © 2016 M/Gateway Developments Ltd
Applicable for Any DocumentNode
These methods can be applied at any level within an on-disk Document
var dnode = new this.documentStore.DocumentNode('myDoc', ['d' ]);
var myObj = { // create the object shown to the right };
dnode.setDocument(myObj);
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d","e1","f1a")="bar1a"
myDoc("d","e1","f2a")="bar2a"
myDoc("d","e2","f1b")="bar1b"
myDoc("d","e2","f2b")="bar2b"
myDoc("d","e2","f3b")="bar3b"
myDoc("d","g")=1000
myDoc("d","h2","w1")="foo"
myDoc("d","h2","w2")="bar"
myObj = {
g: 1000,
h2: {
w1: 'foo',
w2: 'bar'
}
}

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What if there's an overlap?
These methods can be applied at any level within an on-disk Document
var dnode = new this.documentStore.DocumentNode('myDoc', ['d' ]);
var myObj = { // create the object shown to the right };
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d","e1","f1a")="bar1a"
myDoc("d","e1","f2a")="bar2a"
myDoc("d","e2","f1b")="bar1b"
myDoc("d","e2","f2b")="bar2b"
myDoc("d","e2","f3b")="bar3b"
myObj = {
e2: {
f3b: 'new value',
f4b: 'bar4b'
},
g: 1000,
h2: {
w1: 'foo',
w2: 'bar'
}
}
?

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Effectively a merge: new replaces old
These methods can be applied at any level within an on-disk Document
var dnode = new this.documentStore.DocumentNode('myDoc', ['d' ]);
var myObj = { // create the object shown to the right };
dnode.setDocument(myObj);
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d","e1","f1a")="bar1a"
myDoc("d","e1","f2a")="bar2a"
myDoc("d","e2","f1b")="bar1b"
myDoc("d","e2","f2b")="bar2b"
myDoc("d","e2","f3b")="new value"
myDoc("d","e2","f4b")="bar4b"
myDoc("d","g")=1000
myDoc("d","h2","w1")="foo"
myDoc("d","h2","w2")="bar"
myObj = {
e2: {
f3b: 'new value',
f4b: 'bar4b'
},
g: 1000,
h2: {
w1: 'foo',
w2: 'bar'
}
}

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Unless you delete the DocumentNode first
These methods can be applied at any level within an on-disk Document
var dnode = new this.documentStore.DocumentNode('myDoc', ['d' ]);
var myObj = { // create the object shown to the right };
dnode.delete();
myObj = {
e2: {
f3b: 'new value',
f4b: 'bar4b'
},
g: 1000,
h2: {
w1: 'foo',
w2: 'bar'
}
}
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d","e1","f1a")="bar1a"
myDoc("d","e1","f2a")="bar2a"
myDoc("d","e2","f1b")="bar1b"
myDoc("d","e2","f2b")="bar2b"
myDoc("d","e2","f3b")="bar3b"

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Unless you delete the DocumentNode first
These methods can be applied at any level within an on-disk Document
var dnode = new this.documentStore.DocumentNode('myDoc', ['d' ]);
var myObj = { // create the object shown to the right };
dnode.delete();
myObj = {
e2: {
f3b: 'new value',
f4b: 'bar4b'
},
g: 1000,
h2: {
w1: 'foo',
w2: 'bar'
}
}
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"

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Unless you delete the DocumentNode first
These methods can be applied at any level within an on-disk Document
var dnode = new this.documentStore.DocumentNode('myDoc', ['d' ]);
var myObj = { // create the object shown to the right };
dnode.delete();
dnode.setDocument(myObj);
myObj = {
e2: {
f3b: 'new value',
f4b: 'bar4b'
},
g: 1000,
h2: {
w1: 'foo',
w2: 'bar'
}
}
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d","e2","f3b")="new value"
myDoc("d","e2","f4b")="bar4b"
myDoc("d","g")=1000
myDoc("d","h2","w1")="foo"
myDoc("d","h2","w2")="bar"

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Advanced features of
getDocument() and setDocument()

Copyright © 2016 M/Gateway Developments Ltd
Mapping Arrays
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",0)="value0"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
Arrays in Global Storage are
by convention only, using
consecutively numbered
integers as subscript values

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Mapping Arrays
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
Arrays in Global Storage are
by convention only, using
consecutively numbered
integers as subscript values
In legacy applications,
numbering is usually from 1

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Mapping Arrays
var myDoc = new this.documentStore.DocumentNode('myDoc');
var myObj = myDoc.getDocument();
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",0)="value0"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: {
"0": "value0",
"1": "value1",
"2": "value2",
"3": "value3",
"4": "value4",
"5": "value5",
"6": "value6"
}
}
getDocument() maps these to an object

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Mapping Arrays
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: [
"value0",
"value1",
"value2",
"value3",
"value4",
"value5",
"value6"
]
}
Why is d not mapped to a JavaScript array?
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",0)="value0"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
?

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Mapping Arrays
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: [
"value0",
"value1",
"value2",
"value3",
"value4",
"value5",
"value6"
]
}
Why is d not mapped to a JavaScript array?
Well, what if item 2 didn't exist on disk?
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",0)="value0"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"

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Mapping Arrays
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: [
"value0",
"value1",
"value3",
"value4",
"value5",
"value6"
]
}
Why is d not mapped to a JavaScript array?
Well, what if item 2 didn't exist on disk?
Element numbers no longer match
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",0)="value0"
myDoc("d",1)="value1"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
myObj.d[2]myDoc("d",3)

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Mapping Arrays
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: [
"value0",
"value1",
"value3",
"value4",
"value5",
"value6"
]
}
Why is d not mapped to a JavaScript array?
Well, what if item 2 didn't exist on disk?
Which is a problem if we use setDocument() again
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",0)="value0"
myDoc("d",1)="value1"
myDoc("d",2)="value3"
myDoc("d",3)="value4"
myDoc("d",4)="value5"
myDoc("d",5)="value6"

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Mapping Arrays
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: [
"value0",
"value1",
"value2",
"value3",
"value4",
"value5",
"value6"
]
}
Why is d not mapped to a JavaScript array?
And what if there was a non-integer subscript
breaking the sequence?
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",0)="value0"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
myDoc("d","foo")="bar"
?

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Mapping Arrays
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: [
"value0",
"value1",
"value2",
"value3",
"value4",
"value5",
"value6"
]
}
Why is d not mapped to a JavaScript array?
Perhaps only map to array if subscripts are an
un-broken sequence of integers?
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",0)="value0"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"

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Mapping Arrays
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: {
"0": "value0",
"1": "value1",
"2": "value2",
"3": "value3",
"4": "value4",
"5": "value5",
"6": "value6"
'foo": "bar"
}}
Why is d not mapped to a JavaScript array?
Perhaps only map to array if subscripts are an
un-broken sequence of integers?
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",0)="value0"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
myDoc("d","foo")="bar"

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Mapping Arrays
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: [
"value0",
"value1",
"value2",
"value3",
"value4",
"value5",
"value6"
….
"not good"
]
}
Why is d not mapped to a JavaScript array?
Perhaps only map to array if subscripts are an
un-broken sequence of integers?
- this would have big performance implications
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",0)="value0"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
…. etc
myDoc('d",301839979)="not good!"

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Mapping Arrays
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: [
"value0",
"value1",
"value2",
"value3",
"value4",
"value5",
"value6"
….
"not good"
]
}
Why is d not mapped to a JavaScript array?
Perhaps only map to array if subscripts are an
un-broken sequence of integers?
- this would have big performance implications
- every subscript value would need checking!
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",0)="value0"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
…. etc
myDoc('d",301839979)="not good!"
Could be millions to check!

Copyright © 2016 M/Gateway Developments Ltd
Mapping Arrays
var myDoc = new this.documentStore.DocumentNode('myDoc');
var myObj = myDoc.getDocument();
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",0)="value0"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: {
"0": "value0",
"1": "value1",
"2": "value2",
"3": "value3",
"4": "value4",
"5": "value5",
"6": "value6"
}
}
getDocument() maps these to an object for performance

Copyright © 2016 M/Gateway Developments Ltd
Mapping Arrays
var myDoc = new this.documentStore.DocumentNode('myDoc');
var myObj = myDoc.getDocument(true);
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",0)="value0"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
If the Global node tree is small, you can force mapping
To an array for continuous integer subscript values starting 0
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: [
"value0",
"value1",
"value2",
"value3",
"value4",
"value5",
"value6"
]
}

Copyright © 2016 M/Gateway Developments Ltd
Mapping Arrays
var myDoc = new this.documentStore.DocumentNode('myDoc');
myDoc.setDocument(myObj)
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",0)="value0"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: {
"0": "value0",
"1": "value1",
"2": "value2",
"3": "value3",
"4": "value4",
"5": "value5",
"6": "value6"
}
}
and for guaranteed unambiguous mapping to/from JavaScript objects

Copyright © 2016 M/Gateway Developments Ltd
Using Mapped Arrays
var myDoc = new this.documentStore.DocumentNode('myDoc');
var myObj = myDoc.getDocument();
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: {
"0": "value0",
"1": "value1",
"2": "value2",
"3": "value3",
"4": "value4",
"5": "value5",
"6": "value6"
}
}
for (var index in myObj.d) {
console.log('element ' + index: ' + myObj.d[index]);
}
Just have to use a for..in loop
instead of a forEach one

Copyright © 2016 M/Gateway Developments Ltd
What about JavaScript Arrays?
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: [
"value0",
"value1",
"value2",
"value3",
"value4",
"value5",
"value6"
]
}
JavaScript has a formal array type
eg myObj.d is a JavaScript array

Copyright © 2016 M/Gateway Developments Ltd
What about JavaScript Arrays?
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: [
"value0",
"value1",
"value2",
"value3",
"value4",
"value5",
"value6"
]
}
JavaScript has a formal array type
eg myObj.d is a JavaScript array
How does setDocument() handle these?

Copyright © 2016 M/Gateway Developments Ltd
setDocument() mapping of Arrays
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: [
"value0",
"value1",
"value2",
"value3",
"value4",
"value5",
"value6"
]
}
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",0)="value0"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
var myDoc = new this.documentStore.DocumentNode('myDoc');
myDoc.delete();
myDoc.setDocument(myObj);

Copyright © 2016 M/Gateway Developments Ltd
setDocument() mapping of Arrays
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: [
"value0",
"value1",
"value2",
"value3",
"value4",
"value5",
"value6"
]
}
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",0)="value0"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
var myDoc = new this.documentStore.DocumentNode('myDoc');
myDoc.delete();
myDoc.setDocument(myObj);
Mapping is to a zero-based sequence of integer subscripts

Copyright © 2016 M/Gateway Developments Ltd
Mapping legacy Global Storage
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: [
"value1",
"value2",
"value3",
"value4",
"value5",
"value6"
]
}
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
var myDoc = new this.documentStore.DocumentNode('myDoc');
myDoc.delete();
myDoc.setDocument(myObj);
What about legacy Mumps integration, where numbering starts from 1?
?

Copyright © 2016 M/Gateway Developments Ltd
Mapping legacy Global Storage
var myDoc = new this.documentStore.DocumentNode('myDoc');
var myObj = myDoc.getDocument();
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: {
"1": "value1",
"2": "value2",
"3": "value3",
"4": "value4",
"5": "value5",
"6": "value6"
}
}
getDocument() mapping will work correctly

Copyright © 2016 M/Gateway Developments Ltd
Mapping legacy Global Storage
var myDoc = new this.documentStore.DocumentNode('myDoc');
myDoc.delete()
myDoc.setDocument(myObj);
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: {
"1": "value1",
"2": "value2",
"3": "value3",
"4": "value4",
"5": "value5",
"6": "value6"
}
}
And the reverse mapping from the object will work correctly

Copyright © 2016 M/Gateway Developments Ltd
setDocument() mapping of Arrays
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: [
"value1",
"value2",
"value3",
"value4",
"value5",
"value6"
]
}
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",0)="value1"
myDoc("d",1)="value2"
myDoc("d",2)="value3"
myDoc("d",3)="value4"
myDoc("d",4)="value5"
myDoc("d",5)="value6"
var myDoc = new this.documentStore.DocumentNode('myDoc');
myDoc.delete();
myDoc.setDocument(myObj);
But setDocument() mapping from arrays is 0 based

Copyright © 2016 M/Gateway Developments Ltd
setDocument() mapping of Arrays
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: [
"value1",
"value2",
"value3",
"value4",
"value5",
"value6"
]
}
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
var myDoc = new this.documentStore.DocumentNode('myDoc');
myDoc.delete();
var offset = 1;
myDoc.setDocument(myObj, offset);
..unless you apply an offset as a 2nd argument

Copyright © 2016 M/Gateway Developments Ltd
Mapping Arrays
var myDoc = new this.documentStore.DocumentNode('myDoc');
var offset = 1;
var myObj = myDoc.getDocument(true, offset);
myDoc("a")=123
myDoc("b","c1")="foo"
myDoc("b","c2")="foo2"
myDoc("d",1)="value1"
myDoc("d",2)="value2"
myDoc("d",3)="value3"
myDoc("d",4)="value4"
myDoc("d",5)="value5"
myDoc("d",6)="value6"
If the Global node tree is small, you can force mapping
To an array for continuous integer subscript values starting 0
myObj = {
a: 123,
b: {
c1: 'foo',
c2: 'foo2'
},
d: [
"value1",
"value2",
"value3",
"value4",
"value5",
"value6"
]
}

Copyright © 2016 M/Gateway Developments Ltd
Uniquely Powerful Document Database
• Fine-grained
– ie can be applied at any level within an on-disk
Document
– Save large document using setDocument()
– Retrieve sub-section via getDocument() applied to an
intermediate DocumentNode
– Can even read/write at the individual name/value pair
level anywhere within an on-disk Document
• Using value property of the DocumentNode