程序包 ohos.data.resultset

类 CombinedResultSet

java.lang.Object

ohos.data.resultset.AbsResultSet

ohos.data.resultset.CombinedResultSet

所有已实现的接口:

ResultSet

public class CombinedResultSet
extends AbsResultSet

Represents a linear result set that combines multiple result sets.

Different types of result sets can be combined in a CombinedResultSet. When the getAllColumnNames() or getColumnTypeForIndex(int) method is called, column names or the column type in the original result set matching the row of the CombinedResultSet is returned.

从以下版本开始:

3

SystemCapability

SystemCapability.Data#DATA_APPDATAMGR

嵌套类概要

从接口继承的嵌套类/接口 ohos.data.resultset.ResultSet

ResultSet.ColumnType

字段概要

从类继承的字段 ohos.data.resultset.AbsResultSet

DEFAULT_POS, isClosed, pos

构造器概要

构造器

构造器	说明
CombinedResultSet(ResultSet[] resultSets)	Instantiate the parameterized constructor of CombinedResultSet.

方法概要

限定符和类型	方法	说明
void	close()	Closes the result set.
String[]	getAllColumnNames()	Obtains the names of all columns in a result set.
byte[]	getBlob(int columnIndex)	Obtains the value of the specified column in the current row as a byte array.
ResultSet.ColumnType	getColumnTypeForIndex(int columnIndex)	Obtains the data type based on the specified column index.
double	getDouble(int columnIndex)	Obtains the value of the specified column in the current row as a double.
float	getFloat(int columnIndex)	Obtains the value of the specified column in the current row as a float.
int	getInt(int columnIndex)	Obtains the value of the specified column in the current row as an int.
long	getLong(int columnIndex)	Obtains the value of the specified column in the current row as a long.
int	getRowCount()	Obtains the number of rows in the result set.
short	getShort(int columnIndex)	Obtains the value of the specified column in the current row as a short.
String	getString(int columnIndex)	Obtains the value of the specified column in the current row as a string.
boolean	goToRow(int rowIndex)	Go to the specified row of the result set.
boolean	isColumnNull(int columnIndex)	Checks whether the value of the specified column in the current row is null.
void	registerObserver(DataObserver observer)	Registers an observer that listens for data changes.
void	unregisterObserver(DataObserver observer)	Deregisters an observer that listens for data changes.

从类继承的方法 ohos.data.resultset.AbsResultSet

finalize, getAffectedByUris, getColumnCount, getColumnIndexForName, getColumnNameForIndex, getExtensions, getRowIndex, goTo, goToFirstRow, goToLastRow, goToNextRow, goToPreviousRow, isAtFirstRow, isAtLastRow, isClosed, isEnded, isStarted, notifyChange, setAffectedByUris, setExtensions

从类继承的方法 java.lang.Object

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

构造器详细资料

CombinedResultSet

public CombinedResultSet(ResultSet[] resultSets)

Instantiate the parameterized constructor of CombinedResultSet.

Initialize the combined result set based on the result set array passed in by the user.

参数:

resultSets - The result set array used to initialize the combined result set.

从以下版本开始:

3

方法详细资料

getRowCount

public int getRowCount()

从接口复制的说明: ResultSet

Obtains the number of rows in the result set.

指定者:

getRowCount 在接口中 ResultSet

指定者:

getRowCount 在类中 AbsResultSet

返回:

Returns the number of rows in the result set.

getAllColumnNames

public String[] getAllColumnNames()

从接口复制的说明: ResultSet

Obtains the names of all columns in a result set.

The column names are returned as a string array, in which the strings are in the same order as the columns in the result set.

指定者:

getAllColumnNames 在接口中 ResultSet

指定者:

getAllColumnNames 在类中 AbsResultSet

返回:

Returns a string array containing all the column names in the result set.

getColumnTypeForIndex

public ResultSet.ColumnType getColumnTypeForIndex(int columnIndex)

从接口复制的说明: ResultSet

Obtains the data type based on the specified column index.

The return value is of the enumeration type, which can be an integer, float, String, Blob, or null.

参数:

columnIndex - Indicates the specified column index.

返回:

Returns the data type of the specified column.

getBlob

public byte[] getBlob(int columnIndex)

从接口复制的说明: ResultSet

Obtains the value of the specified column in the current row as a byte array.

The implementation class determines whether to throw an exception if the value of the specified column in the current row is null or the specified column is not of the Blob type.

指定者:

getBlob 在接口中 ResultSet

指定者:

getBlob 在类中 AbsResultSet

参数:

columnIndex - Indicates the specified column index, which starts from 0.

返回:

Returns the value of the specified column as a byte array.

getString

public String getString(int columnIndex)

从接口复制的说明: ResultSet

Obtains the value of the specified column in the current row as a string.

The implementation class determines whether to throw an exception if the value of the specified column in the current row is null or the specified column is not of the string type.

指定者:

getString 在接口中 ResultSet

指定者:

getString 在类中 AbsResultSet

参数:

columnIndex - Indicates the specified column index, which starts from 0.

返回:

Returns the value of the specified column as a string.

getShort

public short getShort(int columnIndex)

从接口复制的说明: ResultSet

Obtains the value of the specified column in the current row as a short.

he implementation class determines whether to throw an exception if the value of the specified column in the current row is null, the specified column is not of the integer type, or the integer is beyond the range [Short.MIN_VALUE, Short.MAX_VALUE].

指定者:

getShort 在接口中 ResultSet

指定者:

getShort 在类中 AbsResultSet

参数:

columnIndex - Indicates the specified column index, which starts from 0.

返回:

Returns the value of the specified column as a short.

getInt

public int getInt(int columnIndex)

从接口复制的说明: ResultSet

Obtains the value of the specified column in the current row as an int.

The implementation class determines whether to throw an exception if the value of the specified column in the current row is null, the specified column is not of the integer type, or the integer is beyond the range [Integer.MIN_VALUE, Integer.MAX_VALUE].

指定者:

getInt 在接口中 ResultSet

指定者:

getInt 在类中 AbsResultSet

参数:

columnIndex - Indicates the specified column index, which starts from 0.

返回:

Returns the value of the specified column as an int.

getLong

public long getLong(int columnIndex)

从接口复制的说明: ResultSet

Obtains the value of the specified column in the current row as a long.

The implementation class determines whether to throw an exception if the value of the specified column in the current row is null, the specified column is not of the integer type, or the integer is beyond the range [Long.MIN_VALUE, Long.MAX_VALUE].

指定者:

getLong 在接口中 ResultSet

指定者:

getLong 在类中 AbsResultSet

参数:

columnIndex - Indicates the specified column index, which starts from 0.

返回:

Returns the value of the specified column as a long.

getFloat

public float getFloat(int columnIndex)

从接口复制的说明: ResultSet

Obtains the value of the specified column in the current row as a float.

The implementation class determines whether to throw an exception if the value of the specified column in the current row is null, the specified column is not of the floating-point type, or the floating-point value cannot be represented by a float.

指定者:

getFloat 在接口中 ResultSet

指定者:

getFloat 在类中 AbsResultSet

参数:

columnIndex - Indicates the specified column index, which starts from 0.

返回:

Returns the value of the specified column as a float.

getDouble

public double getDouble(int columnIndex)

从接口复制的说明: ResultSet

Obtains the value of the specified column in the current row as a double.

The implementation class determines whether to throw an exception if the value of the specified column in the current row is null, the specified column is not of the floating-point type, or the floating-point value cannot be represented by a double.

指定者:

getDouble 在接口中 ResultSet

指定者:

getDouble 在类中 AbsResultSet

参数:

columnIndex - Indicates the specified column index, which starts from 0.

返回:

Returns the value of the specified column as a double.

isColumnNull

public boolean isColumnNull(int columnIndex)

从接口复制的说明: ResultSet

Checks whether the value of the specified column in the current row is null.

指定者:

isColumnNull 在接口中 ResultSet

指定者:

isColumnNull 在类中 AbsResultSet

参数:

columnIndex - Indicates the specified column index, which starts from 0.

返回:

Returns true if the value of the specified column in the current row is null; returns false otherwise.

close

public void close()

从接口复制的说明: ResultSet

Closes the result set.

Calling this method on the result set will release all of its resources and makes it ineffective.

指定者:

close 在接口中 ResultSet

覆盖:

close 在类中 AbsResultSet

另请参阅:

ResultSet.isClosed()

goToRow

public boolean goToRow(int rowIndex)

从接口复制的说明: ResultSet

Go to the specified row of the result set.

指定者:

goToRow 在接口中 ResultSet

指定者:

goToRow 在类中 AbsResultSet

参数:

rowIndex - Indicates the index of the specified row, which starts from 0.

返回:

Returns true if the result set is moved successfully; returns false otherwise.

registerObserver

public void registerObserver(DataObserver observer)

从接口复制的说明: ResultSet

Registers an observer that listens for data changes.

When a notification of the change of data with a specified URI is received, this observer will be triggered.

指定者:

registerObserver 在接口中 ResultSet

覆盖:

registerObserver 在类中 AbsResultSet

参数:

observer - Indicates the observer to be registered.

另请参阅:

ResultSet.setAffectedByUris(java.lang.Object, java.util.List<ohos.utils.net.Uri>), ResultSet.unregisterObserver(ohos.data.rdb.DataObserver)

unregisterObserver

public void unregisterObserver(DataObserver observer)

从接口复制的说明: ResultSet

Deregisters an observer that listens for data changes.

This method is used to release the observer before the component to which the observer belongs is destroyed.

指定者:

unregisterObserver 在接口中 ResultSet

覆盖:

unregisterObserver 在类中 AbsResultSet

参数:

observer - Indicates the observer to be deregistered.