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  • Records read
  • Browsing a data file
  • Memos
  • Locks
  • Various
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Stored procedures
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. HState is used to find out the record status (active, crossed or deleted).
In most cases, HRead 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 HRead:
  • the specified record number does not exist (greater than the total number of records or negative): no reading is performed and HOut returns True.
  • the specified record number does not exist anymore (crossed record, deleted record, ...): no read operation is performed and HOut returns False.
    Use HState to find out the record status.
  • the data file is empty: HOut returns True.
  • the function tries to lock a record that is already locked in read-only: HErrorLock returns True and HOut returns True.

This function can be used with the data files (indexed or not) and with the HFSQL views.
Note: From version 19, HFSQL is the new name of HyperFileSQL.
Example
// Sequential browse to display the name of all customers
i is int
FOR i = 1 _TO_ HNbRec(CUSTOMER, hStateAll)
HRead(CUSTOMER, i)
IF HState() = hStateActive THEN
Info("Customer name: " + CUSTOMER.NAME)
END
END
Syntax
<Result> = HRead([<File name> [, <Record number> [, <Options>]]])
<Result>: Boolean
  • True if the record was read,
  • False if an error occurred (lock, end of data file, ...): the record is not read. HError is used to identify the error.
<File name>: Optional character string (with or without quotes)
Name of HFSQL data file, view or query used.
If this parameter corresponds to an empty string (""), HRead handles the last data file used by the last function for HFSQL management (starting with the letter H).
<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), HRead handles the current record.
OLE DBNative Connectors (Native Accesses) HRead 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.
<Options>: Optional constant
Configures the lock performed on the record read by HRead:
hLockNoNo lock (even if HStartLock was called): the record can be read or modified by another application during the reading.
hLockWriteLock in write mode: the record currently read can be read by another application but it cannot be modified by another application.
hLockReadWriteLock in read/write: the record currently read cannot be read or modified by another application.
Hyper File 5.5 The lock options are ignored. Use the lock functions (HLockRecNum) kept for backward compatibility.
OLE DBNative Connectors (Native Accesses) The lock options will have no effect if the locks are not supported by the OLE DB provider or by the Native Access.
Remarks
WEBDEV - Server codeAjaxHFSQLHFSQL Client/ServerStored proceduresHyper File 5.5

Records read

HRead 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

HRead cannot be used to continue a browse started by HReadFirst, HReadNext.

Memos

The memos associated with the record can be automatically read (or not) when reading the record. HSetMemo 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 (HExtractMemo).
WEBDEV - Server codeAjaxHFSQLHFSQL Client/ServerStored proceduresHyper File 5.5OLE DBNative Connectors (Native Accesses)

Locks

By default (<Options> not specified), no lock operation is performed on the record.
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.
OLE DBNative Connectors (Native Accesses) The lock options will have no effect if the locks are not supported by the OLE DB provider or by the Native Access.

Various

The result of HFound must be ignored (HFound must be used for the searches performed by HReadSeekFirst and HReadSeekLast).
The current record number is returned by HRecNum. The first record found in the data file is record #1.
Component : wd240hf.dll
Minimum version required
  • Version 9
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