Table E and FILEORG X'100' files (File architecture) - Revision history

JAL: /* Null strings and Large Objects */ add link

2015-05-22T19:34:28Z

Null strings and Large Objects: add link

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	</table>		</table>

	<p class="note"><b>Note:</b> The field will always act as if it is physically present (and return a null). However, ~~exactly~~-~~one~~ fields react a bit differently depending on whether they are inside a field group or not. Inside a field group, all three operations will result in a field being present (as displayed in a PAI). Outside of field groups, (and remembering that only the CHANGE statement can be used on ~~exactly~~-~~one~~ fields) only the 'CHANGE ''fieldname'' TO %X' syntax will physically create an occurrence on the record. </p>		<p class="note"><b>Note:</b> The field will always act as if it is physically present (and return a null). However, <var>EXACTLY-ONE</var> fields react a bit differently depending on whether they are inside a field group or not. Inside a field group, all three operations will result in a field being present (as displayed in a <var>[[PAI statement\|PAI]]</var>). Outside of field groups, (and remembering that only the <var>CHANGE</var> statement can be used on <var>EXACTLY-ONE</var> fields) only the <var>CHANGE <i>fieldname</i> TO <i>%x</i></var> syntax will physically create an occurrence on the record. </p>

	==Parameters and commands relating to the use of Table E==		==Parameters and commands relating to the use of Table E==

ELowell at 18:51, 12 May 2014

2014-05-12T18:51:06Z

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	<li>Reorganizing or [[CREATE command: File\|creating]] a file with <var>[[ESIZE parameter\|ESIZE]]</var> greater than 0.		<li>Reorganizing or [[CREATE command: File\|creating]] a file with <var>[[ESIZE parameter\|ESIZE]]</var> greater than 0.

	<li>[[DEFINE FIELD command\|Defining one or more fields]] with an attribute of [[Field design ~~(File management)~~#BLOB.2C CLOB and MINLOBE attributes\|CLOB or BLOB]]. (The file must have an <var>ESIZE</var> for its fields to be defined as <var>CLOB</var> or <var>BLOB</var>.)		<li>[[DEFINE FIELD command\|Defining one or more fields]] with an attribute of [[Field design#BLOB.2C CLOB and MINLOBE attributes\|CLOB or BLOB]]. (The file must have an <var>ESIZE</var> for its fields to be defined as <var>CLOB</var> or <var>BLOB</var>.)
	</ol>		</ol>

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	<li>Because the LOBs no longer need to be contiguous, space monitoring is simpler and Table E is less likely to fill up. </li>		<li>Because the LOBs no longer need to be contiguous, space monitoring is simpler and Table E is less likely to fill up. </li>

	<li>You can define fields so that "small" LOBs can be stored "locally" in the record (and so do not use an entire page in Table E). See [[Field design ~~(File management)~~#Using the MINLOBE attribute\|Using the MINLOBE attribute]]. </li>		<li>You can define fields so that "small" LOBs can be stored "locally" in the record (and so do not use an entire page in Table E). See [[Field design#Using the MINLOBE attribute\|Using the MINLOBE attribute]]. </li>

	<li>You no longer need to predict (using the [[Data maintenance#ADD_statement\|RESERVE clause]]) the size to which a LOB field might grow. </li>		<li>You no longer need to predict (using the [[Data maintenance#ADD_statement\|RESERVE clause]]) the size to which a LOB field might grow. </li>
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	==Storing Large Objects==		==Storing Large Objects==
	<p>		<p>
	Defining a field as a large object (LOB) using the [[Field design ~~(File management)~~#BLOB attribute\|BLOB]] or [[Field design ~~(File management)~~ #CLOB attribute\|CLOB attribute]] stores a pointer in the record in Table B or Table X. Storage of the LOB value depends on the [[Field design ~~(File management)~~#MINLOBE attribute\|MINLOBE attribute]] and the length of the value being stored, as described below.</p>		Defining a field as a large object (LOB) using the [[Field design#BLOB attribute\|BLOB]] or [[Field design#CLOB attribute\|CLOB attribute]] stores a pointer in the record in Table B or Table X. Storage of the LOB value depends on the [[Field design#MINLOBE attribute\|MINLOBE attribute]] and the length of the value being stored, as described below.</p>

	===Pointer in the record===		===Pointer in the record===
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	=== Storing a Large Object ===		=== Storing a Large Object ===
	When the length of the value being stored is 0 (a null string), the action taken depends on the "repeating" type ([[Field design ~~(File management)~~#AT-MOST-ONE, REPEATABLE and EXACTLY-ONE attributes\|AT-MOST-ONE, REPEATABLE, and EXACTLY-ONE attributes]]) as discussed in the next section.		When the length of the value being stored is 0 (a null string), the action taken depends on the "repeating" type ([[Field design#AT-MOST-ONE, REPEATABLE and EXACTLY-ONE attributes\|AT-MOST-ONE, REPEATABLE, and EXACTLY-ONE attributes]]) as discussed in the next section.
	<p>		<p>
	Other than null strings, if the value being stored is less than or equal to the <var>MINLOBE</var> attribute for the field, the value is stored directly in the record (Table B or Table X). Note that this value is in addition to the pointer described above.</p>		Other than null strings, if the value being stored is less than or equal to the <var>MINLOBE</var> attribute for the field, the value is stored directly in the record (Table B or Table X). Note that this value is in addition to the pointer described above.</p>
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	====Null strings and Large Objects====		====Null strings and Large Objects====
	The [[Field design ~~(File management)~~#STORE-DEFAULT (SD) and STORE-NULL (SN) attributes\|STORE-DEFAULT (SD) and STORE-NULL (SN) attributes]] cannot be set on LOB fields like they can on other field types. This restriction results in LOB fields having the equivalent of the LITeral option. The following table illustrates the results when null strings are stored in Large Object fields:		The [[Field design#STORE-DEFAULT (SD) and STORE-NULL (SN) attributes\|STORE-DEFAULT (SD) and STORE-NULL (SN) attributes]] cannot be set on LOB fields like they can on other field types. This restriction results in LOB fields having the equivalent of the LITeral option. The following table illustrates the results when null strings are stored in Large Object fields:

	<table class="thJustBold" style="width:90%">		<table class="thJustBold" style="width:90%">

JAL at 00:40, 28 January 2014

2014-01-28T00:40:35Z

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	<span class="pageSubtitle">Holds Large Object data (BLOBs and CLOBs)</span>		<span class="pageSubtitle">Holds Large Object data (BLOBs and CLOBs)</span>

	Storage and manipulation of Large Objects (LOBs) differs greatly depending on whether <var>FILEORG</var> X'100' is set for the file. This page discusses working with <var>FILEORG</var> X'100' files; for a parallel discussion of working with LOBs in files where FILEORG X'100' is ''not'' set, see [[Table E non X'100' (File architecture)]]. For a summary of the differences between working with LOB data in files where <var>FILEORG</var> X'100' is set and files where it is not, see [[Table E (File architecture)]].		Storage and manipulation of Large Objects (LOBs) differs greatly depending on whether <var>FILEORG</var> X'100' is set for the file. This page discusses working with <var>FILEORG</var> X'100' files; for a parallel discussion of working with LOBs in files where FILEORG X'100' is ''not'' set, see [[Table E and non-FILEORG X'100' files (File architecture)]]. For a summary of the differences between working with LOB data in files where <var>FILEORG</var> X'100' is set and files where it is not, see [[Table E (File architecture)]].

	When the <var>[[FILEORG parameter\|FILEORG]]</var> X'100' bit is set on a file, you enable large object data storage by:		When the <var>[[FILEORG parameter\|FILEORG]]</var> X'100' bit is set on a file, you enable large object data storage by:

Admin: Admin moved page Table E FILEORG x'100' (File architecture) to Table E and FILEORG X'100' files (File architecture) without leaving a redirect

2014-01-28T00:39:09Z

Admin moved page Table E FILEORG x'100' (File architecture) to Table E and FILEORG X'100' files (File architecture) without leaving a redirect

← Older revision	Revision as of 00:39, 28 January 2014
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JAL at 23:58, 27 January 2014

2014-01-27T23:58:44Z

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JAL at 21:25, 2 January 2014

2014-01-02T21:25:23Z

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	Holds Large Object Data (BLOBs and CLOBs)		<span class="pageSubtitle">Holds Large Object Data (BLOBs and CLOBs)</span>

	When FILEORG x'100' is set on a file, large object data storage is enabled by reorganizing or [[CREATE command: File\|creating]] a file with [[ESIZE parameter\|ESIZE]] greater than 0, and then [[DEFINE FIELD command\|defining one or more fields]] with an attribute of [[Field design (File management)#BLOB.2C CLOB and MINLOBE attributes\|CLOB or BLOB]]. (The file must have an ESIZE for its fields to be defined as CLOB or BLOB.)		When FILEORG x'100' is set on a file, large object data storage is enabled by reorganizing or [[CREATE command: File\|creating]] a file with [[ESIZE parameter\|ESIZE]] greater than 0, and then [[DEFINE FIELD command\|defining one or more fields]] with an attribute of [[Field design (File management)#BLOB.2C CLOB and MINLOBE attributes\|CLOB or BLOB]]. (The file must have an ESIZE for its fields to be defined as CLOB or BLOB.)

JAL at 21:20, 2 January 2014

2014-01-02T21:20:52Z

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	*Because the LOBs no longer need to be contiguous, space monitoring is simpler and Table E is less likely to fill up.		*Because the LOBs no longer need to be contiguous, space monitoring is simpler and Table E is less likely to fill up.
	*You can define fields so that 'small' LOBs can be stored 'locally' in the record (and so do not use an entire page in Table E). See the [[Field design (File management)#Using the MINLOBE attribute\|MINLOBE attribute]].		*You can define fields so that 'small' LOBs can be stored 'locally' in the record (and so do not use an entire page in Table E). See the [[Field design (File management)#Using the MINLOBE attribute\|MINLOBE attribute]].
	*You no longer need to predict (using the [[~~Data_Maintenance~~#ADD_statement\|RESERVE clause]]) the size that a LOB field might grow to.</p>		*You no longer need to predict (using the [[Data maintenance#ADD_statement\|RESERVE clause]]) the size that a LOB field might grow to.</p>

	== Storing Large Objects ==		== Storing Large Objects ==

Admin: Admin moved page Table E FILEORG x'100' (File Architecture) to Table E FILEORG x'100' (File architecture) without leaving a redirect

2013-12-18T22:38:07Z

Admin moved page Table E FILEORG x'100' (File Architecture) to Table E FILEORG x'100' (File architecture) without leaving a redirect

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ELowell at 20:31, 16 December 2013

2013-12-16T20:31:45Z

ELowell at 19:54, 16 December 2013

2013-12-16T19:54:26Z

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	When FILEORG x'100' is set on a file, large object data storage is enabled by reorganizing or [[CREATE command: File\|creating]] a file with [[ESIZE parameter\|ESIZE]] greater than 0, and then [[DEFINE FIELD command\|defining one or more fields]] with an attribute of [[~~Field_Design_~~(~~File_Management~~)#BLOB.~~2C_CLOB_and_MINLOBE_attributes~~\|CLOB or BLOB]]. (The file must have an ESIZE for its fields to be defined as CLOB or BLOB.)		When FILEORG x'100' is set on a file, large object data storage is enabled by reorganizing or [[CREATE command: File\|creating]] a file with [[ESIZE parameter\|ESIZE]] greater than 0, and then [[DEFINE FIELD command\|defining one or more fields]] with an attribute of [[Field design (File management)#BLOB.2C CLOB and MINLOBE attributes\|CLOB or BLOB]]. (The file must have an ESIZE for its fields to be defined as CLOB or BLOB.)

	Available as of Model 204 V7.5.		Available as of Model 204 V7.5.

← Older revision		Revision as of 20:31, 16 December 2013
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	Holds Large Object Data (BLOBs and CLOBs)		Holds Large Object Data (BLOBs and CLOBs)


	When FILEORG x'100' is set on a file, large object data storage is enabled by reorganizing or [[CREATE command: File\|creating]] a file with [[ESIZE parameter\|ESIZE]] greater than 0, and then [[DEFINE FIELD command\|defining one or more fields]] with an attribute of [[Field design (File management)#BLOB.2C CLOB and MINLOBE attributes\|CLOB or BLOB]]. (The file must have an ESIZE for its fields to be defined as CLOB or BLOB.)		When FILEORG x'100' is set on a file, large object data storage is enabled by reorganizing or [[CREATE command: File\|creating]] a file with [[ESIZE parameter\|ESIZE]] greater than 0, and then [[DEFINE FIELD command\|defining one or more fields]] with an attribute of [[Field design (File management)#BLOB.2C CLOB and MINLOBE attributes\|CLOB or BLOB]]. (The file must have an ESIZE for its fields to be defined as CLOB or BLOB.)
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	<p>Storing chained LOBs has the following advantages over storing and accessing LOBs in non x'100' files:		<p>Storing chained LOBs has the following advantages over storing and accessing LOBs in non x'100' files:
	*Because the LOBs no longer need to be contiguous, space monitoring is simpler and Table E is less likely to fill up.		*Because the LOBs no longer need to be contiguous, space monitoring is simpler and Table E is less likely to fill up.
	*You can define fields so that 'small' LOBs can be stored 'locally' in the record (and so do not use an entire page in Table E). See the [[Field ~~Design~~ (File ~~Management~~)#Using the MINLOBE attribute\|MINLOBE attribute]].		*You can define fields so that 'small' LOBs can be stored 'locally' in the record (and so do not use an entire page in Table E). See the [[Field design (File management)#Using the MINLOBE attribute\|MINLOBE attribute]].
	*You no longer need to predict (using the [[Data_Maintenance#ADD_statement\|RESERVE clause]]) the size that a LOB field might grow to.</p>		*You no longer need to predict (using the [[Data_Maintenance#ADD_statement\|RESERVE clause]]) the size that a LOB field might grow to.</p>

	== Storing Large Objects ==		== Storing Large Objects ==

	<p>Defining a field as a large object (LOB) using the [[Field ~~Design~~ (File ~~Management~~)#BLOB attribute\|BLOB]] or [[Field ~~Design~~ (File ~~Management~~) #CLOB attribute\|CLOB attribute]] stores a pointer in the record in Table B or Table X. Storage of the LOB value depends on the [[Field ~~Design~~ (File ~~Management~~)#MINLOBE attribute\|MINLOBE attribute]] and length of the value being stored, as described below.</p>		<p>Defining a field as a large object (LOB) using the [[Field design (File management)#BLOB attribute\|BLOB]] or [[Field design (File management) #CLOB attribute\|CLOB attribute]] stores a pointer in the record in Table B or Table X. Storage of the LOB value depends on the [[Field design (File management)#MINLOBE attribute\|MINLOBE attribute]] and length of the value being stored, as described below.</p>

	=== Pointer in the record ===		=== Pointer in the record ===
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	=== Storing a Large Object ===		=== Storing a Large Object ===

	When the length of the value being stored is 0 (a null string), the action taken depends on the 'repeating' type ([[Field ~~Design~~ (File ~~Management~~)#AT-MOST-ONE, REPEATABLE and EXACTLY-ONE attributes\|AT-MOST-ONE, REPEATABLE and EXACTLY-ONE attributes]]) as discussed in the next section.		When the length of the value being stored is 0 (a null string), the action taken depends on the 'repeating' type ([[Field design (File management)#AT-MOST-ONE, REPEATABLE and EXACTLY-ONE attributes\|AT-MOST-ONE, REPEATABLE and EXACTLY-ONE attributes]]) as discussed in the next section.
	<p>Other than null strings, if the value being stored is less than or equal to the [[Field ~~Design~~ (File ~~Management~~)#MINLOBE attribute\|MINLOBE attribute]] for the field, then the value is stored directly in the record (Table B or Table X). Note that this value is in addition to the pointer described above.</p>		<p>Other than null strings, if the value being stored is less than or equal to the [[Field design (File management)#MINLOBE attribute\|MINLOBE attribute]] for the field, then the value is stored directly in the record (Table B or Table X). Note that this value is in addition to the pointer described above.</p>
	<p>If the length of the value being stored is greater than the [[Field ~~Design~~ (File ~~Management~~)#MINLOBE attribute\|MINLOBE attribute]] for the field, the value is stored in a series of pages in Table E with the first (up to) 6140 bytes (4 bytes being reserved for the chain pointer) on the first page, the next (up to) 6140 bytes on the 'next' page, and so on. These pages are not necessarily contiguous. Any pages emptied by LOB deletes are first reused before the pages at [[EHIGHPG parameter\|EHIGHPG]] are used. </p>		<p>If the length of the value being stored is greater than the [[Field design (File management)#MINLOBE attribute\|MINLOBE attribute]] for the field, the value is stored in a series of pages in Table E with the first (up to) 6140 bytes (4 bytes being reserved for the chain pointer) on the first page, the next (up to) 6140 bytes on the 'next' page, and so on. These pages are not necessarily contiguous. Any pages emptied by LOB deletes are first reused before the pages at [[EHIGHPG parameter\|EHIGHPG]] are used. </p>

	==== Null Strings and Large Objects ====		==== Null Strings and Large Objects ====

	The [[Field ~~Design~~ (File ~~Management~~)#STORE-DEFAULT (SD) and STORE-NULL (SN) attributes\|STORE-DEFAULT (SD) and STORE-NULL (SN) attributes]] cannot be set on LOB fields like they can on other field types. This restriction results in LOB fields having the equivalent of the LITeral option. The following table illustrates the results when null strings are stored in Large Object fields:		The [[Field design (File management)#STORE-DEFAULT (SD) and STORE-NULL (SN) attributes\|STORE-DEFAULT (SD) and STORE-NULL (SN) attributes]] cannot be set on LOB fields like they can on other field types. This restriction results in LOB fields having the equivalent of the LITeral option. The following table illustrates the results when null strings are stored in Large Object fields:

	{\| class="wikitable";style="width="90%		{\| class="wikitable";style="width="90%