Explain YDN-DB full-text search usage.
To use full-text search feature, you must use one of the pre-build library containing 'text' module, such as ‘ydn.db-isw-core-e-qry-text.js’. If right mixed of modules are not available in pre-build download page, custom build can be requested for paid user.
A full-text catalog is a logical container for full-text indexes, to make management of groups of full-text indexes easier. Full-text catalog is defined in YDN-DB database schema.
The following full text catalog index author name on first and last field
of record value with weighting more on first.
var schema = {
fullTextCatalogs: [{
name: 'name',
sources: [
{
storeName: 'contact',
keyPath: 'first'
}],
]},
stores: [
{
name: 'contact',
autoIncrement: true
}]
};
Each full-text (inverted) index has source reference to original document by storeName and keyPath. The value of keyPath is the text to be indexed. weight factor is applied when ranking search result. This weight value is not stored in the database can be changed after indexing as well.
Storage instantiation is same, but use schema with fullTextCatalogs attribute as described above. put and add method will trigger full-text indexing process. remove or clear methods will remove full-text index as well.
var db = new ydn.db.Storage('db name', schema);
db.put('contact', [{first: 'Jhon'}, {first: 'Collin'}]);
Full-text search is performed by using search method giving full-text catalog name and query terms.
db.search('name', 'jon').done(function(x) {
console.log(x);
db.get(x[0].storeName, x[0].primaryKey).done(function(top) {
console.log(top);
})
});
Full-text search request return list of inverted index. An inverted index has the following attributes: storeName, primaryKey, score, tokens, representing for store name of original document, primary key of original document, match quality score and array of token objects. Token object has the following attributes: keyPath, value and loc representing key path of index of the original document, original word from the original document and array list of position of word in the document.
Query format is free text, in which implicit and/or/near logic operator apply for each token. Use double quote for exact match, - to subtract from the result and * for prefix search.