New (Recordset constructor): Difference between revisions
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<div id="lockstrength"></div> | <div id="lockstrength"></div> | ||
<tr><th>lockstrength</th> | <tr><th>lockstrength</th> | ||
<td>The lock strength of the instantiated <var>Recordset</var> object. Options are <var>LockStrength</var> enumeration values (<var>None</var>, <var>Share</var>, or <var>Exclusive</var>) | <td>The lock strength of the instantiated <var>Recordset</var> object. Options are <var>LockStrength</var> enumeration values (<var>None</var>, <var>Share</var>, or <var>Exclusive</var>), as described below. This is an optional parameter, and it defaults to <var>Share</var>. | ||
</td></tr> | </td></tr> | ||
<tr><th><var>LoopLockStrength</var></th> | <tr><th><var>LoopLockStrength</var></th> | ||
<td>The lock strength to be used for loops on records in the <var>Recordset</var> object. This is an optional, [[Notation conventions for methods|name required]] parameter, available in <var class="product">Sirius Mods</var> 7.0 and later. It defaults to <var>None</var>. See [[Recordset class#LoopLockStrength for Recordsets|"LoopLockStrength for Recordsets"]]. | <td>The lock strength to be used for loops on records in the <var>Recordset</var> object. This is an optional, [[Notation conventions for methods|name required]] parameter, available in <var class="product">Sirius Mods</var> 7.0 and later. It defaults to <var>None</var>. See [[Recordset class#LoopLockStrength for Recordsets|"LoopLockStrength for Recordsets"]]. | ||
</td></tr></table> | |||
</ | <h3>LockStrength enumeration</h3> | ||
These are the valid values of this enumeration, which correspond to standard <var class="product">Model 204</var> record-locking levels: | |||
<dl> | |||
<dt>None <dd><var>Recordset</var> is not locked. <br> No locks are held on the object, so there is no conflict with others holding <var>Share</var> or <var>Exclusive</var> locks (readers and updaters may proceed). <var>Find Without Locks</var> statements acquire this type of record lock. | |||
<dt>Share <dd><var>Recordset</var> is share locked. <br> This level allows other users to hold a Share lock, but not an Exclusive lock (allows readers but not updaters to proceed). <var>Find All Records</var> statements acquire this type of record lock. <dt>Exclusive <dd><var>Recordset</var> is exclusively locked. <br> This level prohibits others from holding either an <var>Exclusive</var> lock or a <var>Share</var> lock. It is generally used for update. <var>Find And Reserve</var> statements acquire this type of record lock. </dl> | |||
==Usage notes== | ==Usage notes== |
Revision as of 23:54, 17 May 2011
Create a new Recordset object (Recordset class)
This function makes a new, empty instance of a Recordset object.
Syntax
%recordset = [%(Recordset In filOrGrp name):]New[( [lockStrength], - [LoopLockStrength= lockStrength])]
Syntax terms
%newSet | An empty Recordset object created by this method. |
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%(RecordSet) | Either a class name that includes a file context in parentheses, as in %(Recordset in file sirLocal ), or a variable in the class, as in %recSet .
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lockstrength | The lock strength of the instantiated Recordset object. Options are LockStrength enumeration values (None, Share, or Exclusive), as described below. This is an optional parameter, and it defaults to Share. |
LoopLockStrength | The lock strength to be used for loops on records in the Recordset object. This is an optional, name required parameter, available in Sirius Mods 7.0 and later. It defaults to None. See "LoopLockStrength for Recordsets". |
LockStrength enumeration
These are the valid values of this enumeration, which correspond to standard Model 204 record-locking levels:
- None
- Recordset is not locked.
No locks are held on the object, so there is no conflict with others holding Share or Exclusive locks (readers and updaters may proceed). Find Without Locks statements acquire this type of record lock. - Share
- Recordset is share locked.
This level allows other users to hold a Share lock, but not an Exclusive lock (allows readers but not updaters to proceed). Find All Records statements acquire this type of record lock. - Exclusive
- Recordset is exclusively locked.
This level prohibits others from holding either an Exclusive lock or a Share lock. It is generally used for update. Find And Reserve statements acquire this type of record lock.
Usage notes
- Since the created Recordset object is empty, that is, contains no records, New needs to acquire no locks, so it cannot produce a record locking conflict.
- New is typically used in conjunction with AddRecord or AddRecordset, since without these methods, the object created by New is empty and therefore fairly uninteresting.
Examples
Example New statements follow:
%rs is object recordSet in foo %rs = new %rs = new( none ) %rs = new( exclusive ) %rs = new( share )