DbOrderInfo Function |  |
Return and optionally change information about orders and index files.
Namespace: XSharp.RT
Assembly: XSharp.RT (in XSharp.RT.dll) Version: 2.21
SyntaxRequest Example
View Source
If uNewSetting is not specified, DBOrderInfo() returns the current setting.
If uNewSetting is specified, the previous setting is returned.
Parameters
- kInfoType (Optional)
- Type: Usual
Specifies the type of information.
The constants are listed below. Note, however, that not all constants are supported for all RDDs.
Important! DBOI_USER is a constant that returns the minimum value that third-party RDD developers can use for defining new kInfoType parameters. Values less than DBOI_USER are reserved for Computer Associates development. - cIndexFile (Optional)
- Type: Usual
The name of an index file, including an optional drive and directory (no extension should be specified).
Use this argument with cOrder to remove ambiguity when there are two or more orders with the same name in different index files.
If cIndexFile is not open by the current process, a runtime error is raised. - uOrder (Optional)
- Type: Usual
The name of the order about which you want to obtain information or a number representing its position in the order list. (For single-order index files, the order name is the eight-letter index file name.)
Using the order name is the preferred method since the position may be difficult to determine using multiple-order index files. Invalid values are ignored.
If no index file or order is specified, the controlling order is assumed. - uNewSetting (Optional)
- Type: Usual
If specified, this parameter is used to change the value of a setting.
The data type (and whether uNewSetting can be specified), depends on the kInfoType constant and is documented in the Constants section below.
Return Value
Type: UsualIf uNewSetting is not specified, DBOrderInfo() returns the current setting.
If uNewSetting is specified, the previous setting is returned.
Remarks| Constant | Description |
|---|---|
| DBOI_CONDITION | Returns the for condition of the specified order as a string. |
| DBOI_CUSTOM | Returns and optionally sets the logical flag indicating whether the specified order is custom built (for RDDs that support custom built orders). Note that although you can turn the custom built flag on for a standard order by specifying TRUE for the uNewSetting argument, you cannot turn a custom built order into a standard order. Specifying FALSE for uNewSetting is the same as not specifying the argument at all—both return the current setting. |
| DBOI_EXPRESSION | Returns the order key expression of the specified order as a string. |
| DBOI_FILEHANDLE | Returns the handle of the specified index file as an IntPtr. |
| DBOI_FILESTREAM | Returns the filestream of the specified index file. |
| DBOI_FULLPATH | Returns the full path of the specified index file as a string. |
| DBOI_HPLOCKING | Returns a logical flag indicating whether the specified index file uses the high performance index locking schema (see IndexHPLock() function). |
| DBOI_INDEXEXT | Returns the default index file extension as a string. |
| DBOI_INDEXNAME | Returns the name of the specified index file as a string. |
| DBOI_ISCOND | Returns a logical flag that determines whether the specified order was defined using a for condition. |
| DBOI_ISDESC | Returns the logical flag that determines if the specified order is descending. For drivers that support dynamically setting the descending flag at runtime, specify the new value as a logical, using DBServer:OrderInfo(DBOI_ISDESC, [<oFSIndexFile> | <cIndexFile>], [<cOrder> | <nPosition>], <lNewSetting>). The current setting is returned before it is changed. |
| DBOI_KEYCOUNT | Returns the number of keys in the specified order. |
| DBOI_KEYDEC | Returns the number of decimals in the key of the specified order. |
| DBOI_KEYSINCLUDED | Returns the number of keys included in the specified order so far. This is primarily useful for conditional orders. It can be used during the status display process (with the EVAL clause of the INDEX command). |
| DBOI_KEYSIZE | Returns the size of the key in the specified order as a number. |
| DBOI_KEYTYPE | Returns the data type of the key in the specified order as a string. |
| DBOI_KEYVAL | Returns the key value of the current record in the specified order. |
| DBOI_LOCKOFFSET | Returns the locking offset (see NewIndexLock() function) for the specified index file as a numeric value. |
| DBOI_NAME | Returns the name of the specified order as a string. |
| DBOI_NUMBER | Returns the numeric position of the specified order in the order list. |
| DBOI_ORDERCOUNT | Returns the number of orders defined in the specified index file. |
| DBOI_POSITION | Returns the logical record number of the current record within the specified order. |
| DBOI_RECNO | Returns the physical record number of the current record within the specified order. |
| DBOI_SCOPEBOTTOMs | Returns the bottom boundary of the scope for the specified order. |
| DBOI_SCOPETOP | Returns the top boundary of the scope for the specified order. |
| DBOI_SETCODEBLOCK | Returns the key for the specified order as a code block. |
| DBOI_UNIQUE | Returns a logical flag indicating whether the specified order has the unique attribute set. |
| DBOI_USER | For customizations. |
 Tip |
|---|
| DBOI_USER is a constant that returns the minimum value that third-party RDD developers can use can use for customizations. Values less than DBOI_USER are reserved for X# development. |
It can be made to operate on an unselected work area by specifying it within an aliased expression
Examples
This example uses DBOI_NAME to save the current controlling order.
After changing to a new controlling order, it uses the saved value to restore the original order:
This example uses aliased expressions to return the default index file extension (using DBOI_INDEXEXT) in two different work areas:
In this example, DBOrderInfo(DBOI_INDEXEXT) checks for the existence of the CUSTOMER index file independent of the RDD linked into the current work area:
This example accesses the key expression of several orders from the same index file:
This example uses DBOrderInfo() as part of a TOTAL ON key expression. Since DBOrderInfo() returns the expression as a string, it is specified using a macro expression to force evaluation of the key expression:
In this example, ALL_CUST.MDX contains three orders named CUACCT, CUNAME, CUZIP.
The DBOI_INDEXNAME constant is used to display the name of the index file using one of its orders:
The following example searches for CUNAME in the order list:
This example retrieves the "for condition" from an order:
After changing to a new controlling order, it uses the saved value to restore the original order:
X#
1USE customer INDEX name, serial NEW 2cOrder := DBOrderInfo(DBOI_NAME) // name 3Customer->DBSetOrder("serial") 4? DBOrderInfo(DBOI_NAME) // serial 5Customer->DBSetOrder(cOrder) 6? DBOrderInfo(DBOI_NAME) // name
X#
1USE sales INDEX all_sales VIA "DBFCDX" NEW 2USE customer INDEX name, serial VIA "DBFNTX" NEW 3? Sales->DBOrderInfo(DBOI_INDEXEXT) // .CDX 4? Customer->DBOrderInfo(DBOI_INDEXEXT) // .NTX
X#
1USE customer NEW 2IF !File("customer" + DBOrderInfo(DBOI_INDEXEXT)) 3 Customer->DBCreateIndex("customer", "CustName",; 4 {|| Customer->CustName}) 5ENDIF
X#
1USE customer INDEX all_cust VIA "DBFMDX" NEW 2Customer->DBSetOrder("serial") 3? DBOrderInfo(DBOI_EXPRESSION,, "name") 4// Result: key expression for name order 5? DBOrderInfo(DBOI_EXPRESSION,, "serial") 6// Result: key expression for serial order
X#
1USE sales INDEX salesman NEW 2TOTAL ON &(DBOrderInfo(DBOI_EXPRESSION)) ; 3 FIELDS SaleAmount TO summary
The DBOI_INDEXNAME constant is used to display the name of the index file using one of its orders:
X#
1USE customer VIA "DBFNTX" NEW 2Customer->DBSetIndex("all_cust") 3? DBOrderInfo(DBOI_INDEXNAME,, "cuname") 4// Returns: all_cust
X#
1USE customer VIA "DBFNTX" NEW 2Customer->DBSetIndex("cuacct") 3Customer->DBSetIndex("cuname") 4Customer->DBSetIndex("cuzip") 5? DBOrderInfo(DBOI_NUMBER,, "cuname") // 2
X#
1USE customer NEW 2INDEX ON Customer->Acct TO customer ; 3 FOR Customer->Acct > "AZZZZZ" 4? DBOrderInfo(DBOI_CONDITION,, "customer") 5// Returns: Customer->Acct > "AZZZZZ"
See Also