<Source>.Read (Function)

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<Source>.Read (Function)

In french: <Source>.Lit

Not available with this kind of connection

Reads a record in a data file according to a given record number. This read mode is called "Direct access". The record read is loaded in memory. <Source>.State is used to find out the record status (active, crossed or deleted).

In most cases, <Source>.Read is used to position in the data file in order to perform a read loop by specifying the record number.

Several cases may occur after the call to <Source>.Read:

the specified record number does not exist (greater than the total number of records or negative): no reading is performed and <Source>.Out returns True.
the specified record number does not exist anymore (crossed record, deleted record, ...): no read operation is performed and <Source>.Out returns False.
Use <Source>.State to find out the record status.
the data file is empty: <Source>.Out returns True.
the function tries to lock a record that is already locked in read-only: HErrorLock returns True and <Source>.Out returns True.
Locks are only managed on HFSQL Client/Server data files or data files handled by a Native Access. An HFSQL Mobile record cannot be locked. Indeed, the operating system of Pocket PC does not allow you to lock records.
Access by JDBC: The management of locks is not available for databases accessed by JDBC.

This function can be used with the data files (indexed or not) and with the HFSQL views.

Versions 15 and later

This function is now available for Android applications.

New in version 15

This function is now available for Android applications.

Versions 17 and later

This function is now available for iPhone/iPad applications.

New in version 17

This function is now available for iPhone/iPad applications.

Versions 18 and later

This function is now available in Android Widget mode.

This function is now available in Windows Store apps mode.

New in version 18

This function is now available in Android Widget mode.

This function is now available in Windows Store apps mode.

This function is now available in Android Widget mode.

This function is now available in Windows Store apps mode.

Remark: From version 19, HFSQL is the new name of HyperFileSQL.

Versions 21 and later

This function is now available in Universal Windows 10 App mode.

New in version 21

This function is now available in Universal Windows 10 App mode.

Example

// Sequential browse to display the name of all customers
i is int
FOR i = 1 _TO_ Customer.NbRec(hStateAll)
Customer.Read(i)
IF Customer.State() = hStateActive THEN
Info("Customer name: " + Customer.Name)
END
END

Syntax

<Result> = <Source>.Read([<Record number> [, <Options>]])

<Result>: Boolean

True if the record was read,
False if an error occurred (lock, end of data file, etc.): the record is not read. HError is used to identify the error.

<Source>: Type corresponding to the specified source

Name of HFSQL data file, view or query used.

<Record number>: Optional integer

Number of the record to read.
If this parameter is not specified (or if it is equal to 0 or to the hCurrentRecNum constant), <Source>.Read handles the current record.
<Source>.Read reads the current record. You cannot specify a record number other than the current one. To specify the current record number, use the hCurrentRecNum constant.
Access by JDBC: <Source>.Read reads the current record. You cannot specify a record number other than the current one. To specify the current record, use the hCurrentRecNum constant.

<Options>: Optional constant

Configures the lock set on the record read by <Source>.Read:
hLockNo No lock (even if HStartLock was called): the record can be read or modified by another application during the reading.
hLockWrite Lock in write mode: the record currently read can be read by another application but it cannot be modified by another application.
hLockReadWrite Lock in read/write: the record currently read cannot be read or modified by another application.
Locks are managed only on HFSQL Client/Server data files or on data files handled by a Native Connector. An HFSQL Mobile record cannot be locked. Indeed, the operating system of Pocket PC does not allow you to lock records.
The lock options are ignored. Use the lock functions (<Source>.LockRecNum) kept for backward compatibility.
The lock options will have no effect if the locks are not supported by the OLE DB provider or by the Native Connector.
Access by JDBC: This parameter is ignored.

Remarks

Records read

<Source>.Read is the only function that can be used to access a crossed or deleted record. If the record is deleted, the content of the record is not valid anymore.

Browsing a data file

<Source>.Read cannot be used to continue a browse started by <Source>.ReadFirst, <Source>.ReadNext.

Memos

The memos associated with the record can be automatically read (or not) when reading the record. <Source>.SetMemo is used to customize this automatic read operation.

If the memos are supported, the associated text memos are read when the record is read. The binary memos are read only when they are explicitly used (<Source>.ExtractMemo).

Locks

By default (<Options> not specified), the record is not locked.

If a lock is requested (hLockWrite or hLockReadWrite constant), the record will be read only if this record is not already locked.

There is no need to specify a lock parameter if the data file is locked by HStartLock: the lock specified by HStartLock is automatically taken into account. To ignore the lock specified by HStartLock, use the hLockNo constant.

The lock options will have no effect if the locks are not supported by the OLE DB provider or by the Native Connector.

Various

The result of <Source>.Found must be ignored (<Source>.Found must be used for the searches performed by <Source>.ReadSeekFirst and <Source>.ReadSeekLast).

The current record number is returned by <Source>.RecNum. The first record found in the data file is record #1.

Component: wd260hf.dll