com.couchbase.lite

Class Query

java.lang.Object

com.couchbase.lite.Query

Direct Known Subclasses:

From, 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.

Constructor Summary

Constructors

Constructor and Description
Query()

Method Summary

Modifier and Type	Method and Description
protected void	copy(Query query)
String	explain() Returns a string describing the implementation of the compiled query.
protected DataSource	getFrom()
protected OrderBy	getOrderBy()
protected Select	getSelect()
protected Expression	getWhere()
protected boolean	isDistinct()
ResultSet	run() Runs the query.
static Select	select() Create a SELECT ALL (*) query.
static Select	selectDistinct() Create a SELECT DISTINCT ALL (*) query.
protected void	setDistinct(boolean distinct)
protected void	setFrom(DataSource from)
protected void	setOrderBy(OrderBy orderBy)
protected void	setSelect(Select select)
protected void	setWhere(Expression where)

Methods inherited from class java.lang.Object

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

Constructor Detail

Query

public Query()

Method Detail

select

public static Select select()

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()

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.

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

getSelect

protected Select getSelect()

setSelect

protected void setSelect(Select select)

getFrom

protected DataSource getFrom()

setFrom

protected void setFrom(DataSource from)

getWhere

protected Expression getWhere()

setWhere

protected void setWhere(Expression where)

getOrderBy

protected OrderBy getOrderBy()

setOrderBy

protected void setOrderBy(OrderBy orderBy)

isDistinct

protected boolean isDistinct()

setDistinct

protected void setDistinct(boolean distinct)

copy

protected void copy(Query query)