com.couchbase.lite

Class Query

java.lang.Object

com.couchbase.lite.Query

Direct Known Subclasses:

From, GroupBy, Having, Joins, Limit, OrderBy, Select, Where

public class Query
extends Object

A database query used for querying data from the database. The query statement of the Query object can be fluently constructed by calling the static select methods.

Method Summary

Modifier and Type	Method and Description
String	explain() Returns a string describing the implementation of the compiled query.
Parameters	parameters()
String	profile()
ResultSet	run() Runs the query.
static Select	select(SelectResult... results) Create a SELECT ALL (*) query.
static Select	selectDistinct(SelectResult... results) Create a SELECT DISTINCT ALL (*) query.
LiveQuery	toLive()
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

select

public static Select select(SelectResult... results)

Create a SELECT ALL (*) query. You can then call the Select object's methods such as from() method to construct the complete Query object.

Returns:

the Select object.

selectDistinct

public static Select selectDistinct(SelectResult... results)

Create a SELECT DISTINCT ALL (*) query. You can then call the Select object's methods such as from() method to construct the complete Query object.

Returns:

the Select object.

parameters

public Parameters parameters()

run

public ResultSet run()
              throws CouchbaseLiteException

Runs the query. The returning a result set that enumerates result rows one at a time. You can run the query any number of times, and you can even have multiple ResultSet active at once.

The results come from a snapshot of the database taken at the moment the run() method is called, so they will not reflect any changes made to the database afterwards.

Returns:

the ResultSet for the query result.

Throws:

CouchbaseLiteException - if there is an error when running the query.

explain

public String explain()
               throws CouchbaseLiteException

Returns a string describing the implementation of the compiled query. This is intended to be read by a developer for purposes of optimizing the query, especially to add database indexes. It's not machine-readable and its format may change. As currently implemented, the result is two or more lines separated by newline characters: * The first line is the SQLite SELECT statement. * The subsequent lines are the output of SQLite's "EXPLAIN QUERY PLAN" command applied to that statement; for help interpreting this, see https://www.sqlite.org/eqp.html . The most important thing to know is that if you see "SCAN TABLE", it means that SQLite is doing a slow linear scan of the documents instead of using an index.

Returns:

a string describing the implementation of the compiled query.

Throws:

CouchbaseLiteException - if an error occurs

profile

public String profile()

toLive

public LiveQuery toLive()

toString

public String toString()

Overrides:

toString in class Object