# LOCK for ISAM

> [HTML Version](lock-for-isam.htm)

_Added May 2024_

**LOCK #ch**

Applicable only when LOKSER enabled, LOCK is used to lock the primary index (_ch_) after locating a record using a secondary index. This is automatic when the record is located via the primary index.

**Example**

The following illustrates looking up a record in the secondary index and then deleting it. The LOCK statement is used to first lock the primary index before the delete operation.

OPEN #PCH, "WIDGET", ISAM'INDEXED,  RECSIZ, RECNO    \! primary index \& data

OPEN #SCH, "WIDGET2", ISAM'INDEXED, RECSIZ, RECNO    \! secondary index

...

ISAM #SCH , 1, KEY       \! lookup key in secondary index SCH

IF ERF(SCH) = 33 then

    ? "Record not found"

ELSEIF ERF(SCH) # 0 then

    GOTO ISAM'ERROR

ELSE

    LOCK #PCH            \! lock primary index

    READL #PCH, REC      

    ISAM #SCH, 4, SKEY   \! delete secondary key

    IF ERF(SCH) # 0 GOTO ISAM'ERROR

    ISAM #PCH, 4, PKEY   \! delete primary key

    IF ERF(PCH) # 0 GOTO ISAM'ERROR

    ISAM #PCH, 6, PKEY   \! delete data rec

    IF ERF(PCH) # 0 GOTO ISAM'ERROR

    WRITE #PCH, REC

ENDIF



**See Also**

•	[UNLOKR](unlokr.htm.md)