CHANGE -BLOCK Qualifiers

CHANGE -BLOCK Qualifiers
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This section describes -BLOCK and all of its qualifiers.

-BL[OCK]=block_number

Specifies the block to modify. The -BLOCK qualifier is incompatible with the -FILEHEADER qualifier and all qualifiers related to -FILEHEADER.

-BLOCK is the default qualifier. On commands with neither a -BLOCK nor a -FILEHEADER qualifier, DSE uses the last block handled by a DSE operation. When no block has been accessed, that is, on the first block-oriented command, DSE uses block one (1).

The following qualifiers operate on a block header.

-BS[IZ]=block_size

Changes the block size field of the specified block. Decreasing the block size can result in loss of existing data. The -BSIZ qualifier is incompatible with all qualifiers except -BLOCK, -LEVEL and -TN.


	DSE does not allow you to change the block size to an arbitrary number. It always rounds the block size to the next higher multiple of 512, because database block sizes must always be a multiple of 512. Also, the block size must always be less than or equal to the block size in the file header.

-L[EVEL]=level

Changes the level field for the specified block. The -LEVEL qualifier is incompatible with all qualifiers except -BLOCK, -BSIZ, and -TN.


	DSE lets you change the level of a bitmap block to -1 (the value of the level for a bitmap block) when the bitmap level gets corrupted and takes on an arbitrary value. Note that -1 must be specified in hexadecimal, FF.

Example:

        
        DSE >change -level=FF

-TN[=transaction_number]

Changes the transaction number for the current block. When a CHANGE command does not include a -TN=, DSE sets the transaction number to the current transaction number. Manipulation of the block transaction number affects MUPIP BACKUP -BYTESTREAM, and -ONLINE. The -TN qualifier is incompatible with all qualifiers except -BLOCK, -BSIZ, and -LEVEL.

The following -BLOCK qualifiers operate on a record header.

-OF[FSET]=offset

Specifies the offset, in bytes, of the target record within the block. If the offset does not point to the beginning of a record, DSE rounds down to the last valid record start (for example, CHANGE -OFFSET=10 starts at -OFFSET=A, if that was the last record). The -OFFSET qualifier is incompatible with all qualifiers except -BLOCK, -CMPC, and -RSIZ.

-RE[CORD]=record_number

Specifies the record number of the target record. The -RECORD qualifier is incompatible with all qualifiers except -BLOCK, -CMPC, and -RSIZ.

-CM[PC]=compression_count

Changes the compression count field of the specified record. Because compression counts propagate from the "front" of the block, this can potentially change the keys of all records following it in the block. If the goal is to change only a single record, it may be preferable to add a new record and remove the old one. The -CMPC qualifier is incompatible with all qualifiers except -BLOCK, -OFFSET, -RECORD, and -RSIZ.

-RS[IZ]=record_size

Changes the record size field of the specified record. The -RSIZ qualifier is incompatible with all qualifiers except -CMPC, -OFFSET, and -RECORD.


	Changing this number impacts all records following it in the block.