OH_Cursor

typedef struct {...} OH_Cursor

Overview

Defines a struct for a result set. Provides APIs to access the result set obtained by querying the RDB store.

Since: 10

Related module: RDB

Header file: oh_cursor.h

Member Variables

Name	Description
int64_t id	Unique identifier of the OH_Cursor struct.

Member Functions

Name	Description
int (getColumnCount)(OH_Cursor cursor, int *count)	Pointer to the function used to obtain the number of columns in the result set.
int (getColumnType)(OH_Cursor cursor, int32_t columnIndex, OH_ColumnType *columnType)	Pointer to the function used to obtain the column type based on the specified column index.
int (getColumnIndex)(OH_Cursor cursor, const char name, int columnIndex)	Pointer to the function used to obtain the column index based on the specified column name.
int (getColumnName)(OH_Cursor cursor, int32_t columnIndex, char *name, int length)	Pointer to the function used to obtain the column name based on the specified column index.
int (getRowCount)(OH_Cursor cursor, int *count)	Pointer to the function used to obtain the number of rows in the result set.
int (goToNextRow)(OH_Cursor cursor)	Pointer to the function used to go to the next row of the result set.
int (getSize)(OH_Cursor cursor, int32_t columnIndex, size_t *size)	Pointer to the function used to obtain information about the memory required when the column data type in the result set is BLOB or TEXT.
int (getText)(OH_Cursor cursor, int32_t columnIndex, char *value, int length)	Pointer to the function used to obtain the value of the string type based on the specified column and the current row.
int (getInt64)(OH_Cursor cursor, int32_t columnIndex, int64_t *value)	Pointer to the function used to obtain the value of the int64_t type based on the specified column and the current row.
int (getReal)(OH_Cursor cursor, int32_t columnIndex, double *value)	Pointer to the function used to obtain the value of the double type based on the specified column and the current row.
int (getBlob)(OH_Cursor cursor, int32_t columnIndex, unsigned char *value, int length)	Pointer to the function used to obtain the values in the form of a byte array based on the specified column and the current row.
int (isNull)(OH_Cursor cursor, int32_t columnIndex, bool *isNull)	Pointer to the function used to check whether the value in the specified column is null.
int (destroy)(OH_Cursor cursor)	Pointer to the function used to destroy a result set.
int (getAsset)(OH_Cursor cursor, int32_t columnIndex, Data_Asset *value)	Pointer to the function used to obtain the value of the asset type based on the specified column and the current row.
int (getAssets)(OH_Cursor cursor, int32_t columnIndex, Data_Asset *value, uint32_t length)	Pointer to the function used to obtain the values in the form of an asset array based on the specified column and the current row.

Member Function Description

getColumnCount()

int (*getColumnCount)(OH_Cursor *cursor, int *count)

Description

Pointer to the function used to obtain the number of columns in the result set.

Since: 10

Parameters

Name	Description
OH_Cursor *cursor	Pointer to the OH_Cursor instance.
int *count	Pointer to the number of columns in the result set obtained.

Returns

Type	Description
int	Returns RDB_OK if the operation is successful; returns an error code otherwise.

getColumnType()

int (*getColumnType)(OH_Cursor *cursor, int32_t columnIndex, OH_ColumnType *columnType)

Description

Pointer to the function used to obtain the column type based on the specified column index.

Since: 10

Parameters

Name	Description
OH_Cursor *cursor	Pointer to the OH_Cursor instance.
int32_t columnIndex	Index of the column, which starts from 0.
OH_ColumnType *columnType	Pointer to OH_ColumnType of columns in the result set obtained.

Returns

Type	Description
int	Returns RDB_OK if the operation is successful; returns an error code otherwise.

getColumnIndex()

int (*getColumnIndex)(OH_Cursor *cursor, const char *name, int *columnIndex)

Description

Pointer to the function used to obtain the column index based on the specified column name.

Since: 10

Parameters

Name	Description
OH_Cursor *cursor	Pointer to the OH_Cursor instance.
const char *name	Column name.
int *columnIndex	Pointer to the column index obtained.

Returns

Type	Description
int	Returns RDB_OK if the operation is successful; returns an error code otherwise.

getColumnName()

 int (*getColumnName)(OH_Cursor *cursor, int32_t columnIndex, char *name, int length)

Description

Pointer to the function used to obtain the column name based on the specified column index.

Since: 10

Parameters

Name	Description
OH_Cursor *cursor	Pointer to the OH_Cursor instance.
int32_t columnIndex	Index of the column, which starts from 0.
char *name	Pointer to the column name obtained.
int length	Total length of the column name obtained, including the terminator.

Returns

Type	Description
int	Returns RDB_OK if the operation is successful; returns an error code otherwise.

getRowCount()

int (*getRowCount)(OH_Cursor *cursor, int *count)

Description

Pointer to the function used to obtain the number of rows in the result set.

Since: 10

Parameters

Name	Description
OH_Cursor *cursor	Pointer to the OH_Cursor instance.
int *count	Pointer to the number of columns in the result set obtained.

Returns

Type	Description
int	Returns RDB_OK if the operation is successful; returns an error code otherwise.

goToNextRow()

 int (*goToNextRow)(OH_Cursor *cursor)

Description

Pointer to the function used to go to the next row of the result set.

Since: 10

Parameters

Name	Description
OH_Cursor *cursor	Pointer to the OH_Cursor instance.

Returns

Type	Description
int	Returns RDB_OK if the operation is successful; returns an error code otherwise.

getSize()

int (*getSize)(OH_Cursor *cursor, int32_t columnIndex, size_t *size)

Description

Pointer to the function used to obtain information about the memory required when the column data type in the result set is BLOB or TEXT.

Since: 10

Parameters

Name	Description
OH_Cursor *cursor	Pointer to the OH_Cursor instance.
int32_t columnIndex	Index of the column, which starts from 0.
size_t *size	Pointer to the memory size obtained.

Returns

Type	Description
int	Returns RDB_OK if the operation is successful; returns an error code otherwise.

getText()

int (*getText)(OH_Cursor *cursor, int32_t columnIndex, char *value, int length)

Description

Pointer to the function used to obtain the value of the string type based on the specified column and the current row.

Since: 10

Parameters

Name	Description
OH_Cursor *cursor	Pointer to the OH_Cursor instance.
int32_t columnIndex	Index of the column, which starts from 0.
char *value	Pointer to the value of the string type obtained.
int length	Length of value, obtained by using getSize.

Returns

Type	Description
int	Returns RDB_OK if the operation is successful; returns an error code otherwise.

getInt64()

int (*getInt64)(OH_Cursor *cursor, int32_t columnIndex, int64_t *value)

Description

Pointer to the function used to obtain the value of the int64_t type based on the specified column and the current row.

Since: 10

Parameters

Name	Description
OH_Cursor *cursor	Pointer to the OH_Cursor instance.
int32_t columnIndex	Index of the column, which starts from 0.
int64_t *value	Pointer to the value obtained.

Returns

Type	Description
int	Returns RDB_OK if the operation is successful; returns an error code otherwise.

getReal()

int (*getReal)(OH_Cursor *cursor, int32_t columnIndex, double *value)

Description

Pointer to the function used to obtain the value of the double type based on the specified column and the current row.

Since: 10

Parameters

Name	Description
OH_Cursor *cursor	Pointer to the OH_Cursor instance.
int32_t columnIndex	Index of the column, which starts from 0.
double *value	Pointer to the value obtained.

Returns

Type	Description
int	Returns RDB_OK if the operation is successful; returns an error code otherwise.

getBlob()

int (*getBlob)(OH_Cursor *cursor, int32_t columnIndex, unsigned char *value, int length)

Description

Pointer to the function used to obtain the values in the form of a byte array based on the specified column and the current row.

Since: 10

Parameters

Name	Description
OH_Cursor *cursor	Pointer to the OH_Cursor instance.
int32_t columnIndex	Index of the column, which starts from 0.
unsigned char *value	Pointer to the values in the form of a byte array obtained.
int length	Length of value, obtained by using getSize.

Returns

Type	Description
int	Returns RDB_OK if the operation is successful; returns an error code otherwise.

isNull()

int (*isNull)(OH_Cursor *cursor, int32_t columnIndex, bool *isNull)

Description

Pointer to the function used to check whether the value in the specified column is null.

Since: 10

Parameters

Name	Description
OH_Cursor *cursor	Pointer to the OH_Cursor instance.
int32_t columnIndex	Index of the column, which starts from 0.
bool *isNull	Pointer to the value returned. The value true means the value is null; the value false means the opposite.

Returns

Type	Description
int	Returns RDB_OK if the operation is successful; returns an error code otherwise.

destroy()

int (*destroy)(OH_Cursor *cursor)

Description

Pointer to the function used to destroy a result set.

Since: 10

Parameters

Name	Description
OH_Cursor *cursor	Pointer to the OH_Cursor instance.

Returns

Type	Description
int	Returns RDB_OK if the operation is successful; returns an error code otherwise.

getAsset()

int (*getAsset)(OH_Cursor *cursor, int32_t columnIndex, Data_Asset *value)

Description

Pointer to the function used to obtain the value of the asset type based on the specified column and the current row.

Since: 11

Parameters

Name	Description
OH_Cursor *cursor	Pointer to the OH_Cursor instance.
int32_t columnIndex	Index of the column, which starts from 0.
Data_Asset *value	Pointer to the value obtained.

Returns

Type	Description
int	Returns RDB_OK if the operation is successful; returns an error code otherwise.

getAssets()

int (*getAssets)(OH_Cursor *cursor, int32_t columnIndex, Data_Asset **value, uint32_t *length)

Description

Pointer to the function used to obtain the values in the form of an asset array based on the specified column and the current row.

Since: 11

Parameters

Name	Description
OH_Cursor *cursor	Pointer to the OH_Cursor instance.
int32_t columnIndex	Index of the column, which starts from 0.
Data_Asset **value	Double pointer to the value obtained.
uint32_t *length	Pointer to the length of the buffer, which is a variable of the uint32_t type passed in. After the API is executed, the variable is updated to the length of the returned asset array.