app-pouchdb-conflict-resolution enables declarative configuration of conflict
resolution strategies ordered by logical relationships in the DOM. Currently
two basic strategies are supported: firstWriteWins and lastWriteWins.
To use app-pouchdb-conflict-resolution, simply include the element somewhere
in a document subtree at or above the ShadowRoot of an app-pouchdb-document
or app-pouchdb-query:
<app-pouchdb-conflict-resolution
strategy="lastWriteWins">
</app-pouchdb-conflict-resolution>
<app-pouchdb-document
db-name="cats"
doc-id="parsnip">
</app-pouchdb-document>When a conflict occurs, the app-pouchdb-document will request fire an event
to notify of the conflict and request a resolution strategy. The
app-pouchdb-conflict-resolution element listens at its nearest ShadowRoot
boundary for conflict notifications, and responds to them as needed with a
configured strategy.
app-pouchdb-document is an implementation of Polymer.AppStorageBehavior
for reading and writing to individual PouchDB documents.
In order to refer to a PouchDB document, provide the name of the database (both local and remote databases are supported) and the ID of the document.
For example:
<app-pouchdb-document
db-name="cats"
doc-id="parsnip">
</app-pouchdb-document>In the above example, a PouchDB instance will be created to connect to the
local database named "cats". Then it will check to see if a document with the
ID "parsnip" exists. If it does, the data property of the document will be
set to the value of the document. If it does not, then any subsequent
assignments to the data property will cause a document with ID "parsnip" to
be created.
Here is an example of a simple form that can be used to read and write to a PouchDB document:
<app-pouchdb-document
db-name="cats"
doc-id="parsnip"
data="{{cat}}">
</app-pouchdb-document>
<input
is="iron-input"
bind-value="{{cat.name}}">
</input>app-pouchdb-index enables declarative, idempotent configuration of database
indexes. The semantics map to those of the pouchdb-find plugin. For more
information on creating PouchDB indexes with pouchdb-find, please refer to the
documentation
here.
Note: at least one index must be created in order for app-pouchdb-query to
work.
app-pouchdb-query allows for declarative, read-only querying into a PouchDB
database. The semantics for querying match those of the
pouchdb-find plugin.
In order to create an app-pouchdb-query against any field other than _id, at
least one index needs to have been created in your PouchDB database. You can use
app-pouchdb-index to do this declaratively. For example:
<app-pouchdb-index
db-name="cats"
fields='["name"]'>
</app-pouchdb-index>
<app-pouchdb-query
db-name="cats"
selector="name $exists true"
fields='["_id","name"]'
sort='["name"]'
data="{{cats}}">
</app-pouchdb-query>In the above example, an index is created on the "name" field of the "cats" database. This allows the query to select by the "name" field, and sort by the "name" field.
By default, PouchDB creates an index on the "_id" field, so if you don't particularly care about sorting or selecting on other fields, you don't need to create any extra indexes.
This element requires a specialized selector syntax that maps to the semantics of the pouchdb-find plugin. For example, if you wish to create the following selector:
{
series: 'Mario',
debut: { $gt: 1990 }
}You should format the selector property this way:
"series $eq 'Mario', debut $gt 1990"This makes selectors more convenient to write declaratively, while still maintaining the ability to express selectors with full fidelity. For more documentation on pouchdb-find selectors, please check out the docs here.
app-pouchdb-sync arranges for one-directional or bi-directional
synchronization between two PouchDB databases. For one-directional
synchronization, it forwards to PouchDB.replicate, and for bi-directional
synchronization, it forwards to PouchDB.sync.
Here is an example of bi-directional synchronization between a local database and a remote one:
<app-pouchdb-sync
src="cats"
target="https://example.com:5678/cats"
bidirectional>
</app-pouchdb-sync>For more information on PouchDB synchronization topics, please refer to the documentation here.
Polymer.AppPouchDBDatabaseBehavior is an abstract implementation that
is intended to be shared by any element that refers to and operates on a
PouchDB database instance. It includes implementation for creating and
configuring a PouchDB database instance, and some advanced macro
operations that might be performed on the database, including "upsert"
and conflict-aware "put" and "post" operations.