Chapter 3: Caché 3.2.1 Enhancements

Windows 2000 Support

Note: The Caché for Windows 2000 product does not currently support raw Ethernet-based networking (e.g. DDP or LAT). A new packet driver will be available sometime in the future on the InterSystems Web site which will allow these protocols to run.

New SQL Functions

• DATEADD
• DATEDIFF
• DATENAME
• DATEPART
• GETDATE
• TIMESTAMPADD
• TIMESTAMPDIFF

Change to Unique and PrimaryKey Indices

The new index structure for Unique and PrimaryKey indices is better for three reasons:

• Collation is applied to the property values.
• The uniqueness constraint applied is SQL-92 compatible.
• The index is indistinguishable from a non-unique index and will be usable by the query processor.

Note that if the TYPE of an index is not defined, the default type of INDEX is used. Prior to Caché 3.2.1, KEY was the default TYPE for indices defined as Unique or PrimaryKey.

SQL Foreign Key Referential Actions

ON DELETE <ref-action>

ON UPDATE <ref-action>

• NO ACTION
• SET DEFAULT
• SET NULL
• CASCADE

The following example uses both referential action clauses:

CREATE TABLE Patient (
        PatID               VARCHAR(16),
        Name                VARCHAR(30),
        DOB                 DATE,
        Primary_Physician   VARCHAR(16) DEFAULT 'A10001982321',
        CONSTRAINT Patient_PK PRIMARY KEY (PatID),
        CONSTRAINT Patient_Physician_FK FOREIGN KEY
          Primary_Physician REFERENCES Physician (PatID)
          ON UPDATE CASCADE
          ON DELETE SET NULL
        )

These referential action clauses can be used anywhere you can define a Foreign Key constraint, such as a CREATE TABLE statement. For details on syntax and usage, see the Caché SQL Reference.

Physical Cursor Addressing for CHARWIN

Physical cursor addressing mode is the preferred method of dealing with wide characters such as Japanese and Korean (Hangul). When initializing CHARWIN, you must issue the command:

WRITE /INIT("Cache Terminal Wide Characters")

• You have a Unicode version of Caché and have the locale set appropriately, such as "Japan, Japanese, Unicode" (jpnw).
• You have the Caché Configuration Manager set correctly. In the Advanced->ObjectScript panel, set "Physical Cursor Positioning" to Yes.
• In the Caché Terminal, choose:

  Edit->Display Physical Character Setting->Physical

In physical cursor addressing mode, coordinates in /CUP, /WOPEN, etc, represent physical (i.e., narrow) cells. Therefore, it is possible to overwrite just half of a wide character either with a narrow character or part of another wide character. When this happens, the other half of the wide character is turned into a blank.

Note: As part of implementing physical cursor addressing mode, the "Cache Terminal Wide Characters" terminal type was added to ^mtercap.

WRITE /PITCH(n)

Collation Number Change for Japanese Table

Spooling Device Now Correctly Updating $X/$Y Table

• The character
• The default $X/$Y table
• The pitch of the current device

The pitch is the width of wide characters as compared with normal width characters. Its value can be:

• 4 — wide characters are as wide as narrow ones
• 5 — wide characters are 1.25 times as wide as narrow ones
• 6 — wide characters are 1.5 times as wide as narrow ones
• 8 — wide characters are twice as wide as narrow ones

$ZU(86,17,1,value)

For example, to generate a spool to be printed on a device that outputs Kanji Zenkaku (wide) characters so that they are twice as wide as ASCII characters, you would execute:

Open 2 ; open spooler
Use 2 Set oldpitch=$ZU(96,17,1,8)
; your code goes here
Close 2

If $X+$L(string)>132 ...

In Japanese, for instance, there are Zenkaku (wide) and Hankaku (narrow) characters. $Length still returns the number of characters in the string, but $X is updated according to their widths. For example, if Zenkaku characters are twice as wide as the Hankaku ones, outputing a Zenkaku will increase $X by 2. If you are working in such a locale, it is advisable to use $ZWIDTH() in place of $LENGTH(). $ZWIDTH() will return the effective width of the string on the current device. It takes into account the $X/$Y table and the device pitch.

COM Port Section in Configuration Manager

COM Port Enhancements

New OPEN and USE Parameters

OPEN port:(:::"portstate":baudrate)
USE port:(:::"portstate":baudrate)

baudrate is the desired baud rate. The following baud rates are supported (if the hardware permits):

• 110
• 300
• 600
• 1200
• 4800
• 9600
• 14400
• 19200
• 38400
• 56000
• 57600
• 115200
• 128000
• 256000

USE port:/COMPARAMS="portstate"
USE port:/DISCONNECT
USE port:/BAUD=baudrate

For both syntaxes, the Disconnect parameter performs a hangup on modem-controlled ports by lowering the DTR signal for two seconds and then restoring it. The Disconnect does not close the port. The program can dial out again without reopening the COM device.

The Modem Control parameter determines how Caché responds to the state of the RLSD (received line signal detector) pin, which is also known as DCD (data carrier detect). If the line is modem controlled, the state of RLSD is monitored by Caché and an error is generated if a READ command is issued when carrier is not present. A WRITE command does not receive an error when carrier is not present because it must be possible to send the dial command to the modem prior to a connection being established. Caché Modem control checking can be enabled or disabled at any time. It is suggested you turn modem control off while sending commands to the modem and turn it on once carrier is detected and connection has been established.

The DTR Setting option can be used to control login from an attached modem. If the DTR Setting is configured as 0 (zero), then the DTR control signal will be off, and modems will not communicate with the computer. This will prevent a dial-in connection from occurring. If the DTR setting is configured as 1 (one), then the DTR control signal will be on, and modems will communicate with the computer. In this case, dial-in can occur. If you configure DTR off, then you must programmatically set DTR with the OPEN or USE command to be able to dial out using a connected modem. The DTR setting is probably unimportant when using a null modem cable to connect directly to a terminal device or serial printer because the null modem cable should force the DTR control pin on.

Testing the Status with $ZA

If $ZA error reporting is enabled, Comm port errors will be cleared with a call to the Windows ClearCommError() function. The port error state will be reported as follows:

COM Port Definition Section in Configuration File

If input appears at an unowned COM port or if RLSD becomes active on an unowned, modem controlled, COM port, the COM server logs in a new Caché process with the COM port as its principal I/O device. How the process starts up (programmer or application mode, namespace, routine name) is determined by the settings for that COM port established in the Caché Control Panel in the Security, User Accounts section. The format is similar to the way LAT and TELNET ports are tied to a routine. Creating an entry for COM2: will direct logins on port COM2. Creating an entry for COM: will direct logins on all COM ports for which no specific entry exists.

The format of the COM section of the .cpf file is as follows:

[Com]
Com=ON
COM1:=1801X11;19200
...
COMnn:=1801X11;19200

Note that the size of the COM port table is determined by the ttysiz=n,m parameter in the [config] section of the cache.cpf file. The first (n) part ot the ttysiz parameter is the size of the tty table in bytes. The second (m) part of the ttysiz parameter is the number of entries to allocate space for in the COM port table. This parameter can be modified in the Advanced tab of the Caché Configuration Manager by opening the Memory section item and editing the "TTY Name Table" entry.

COM Port Server Utility

info^COMMCTRL

%SYS> d info^COMMCTRL

configured table size = 2
entries in table = 2
ports in table = COM1:,COM2:,
controller PID = 44

update^COMMCTRL

shutdown^COMMCTRL

purge^COMMCTRL

Sample COM Port Routine

ComDemo ;;02:23 PM  16 Feb 2000
COMDEMO ;Demo COM port enhancements.
        ;
        q
        ;
dial(n,number) ;
        ;Dial out on a modem.
        ;Includes debugging information display.
        ;Presumes your modem is set to echo control strings.
        ;Usage:  s port=$$dial(2,"5551234") ;call 555-1234 on COM2:
        ;Return value is "COM"_n_":" on success, "" on failure.
        u 0 w !,"testing dialout"
        s port="COM"_n_":"
        o port:(:"S"):10 e  u 0 w !,"Could not open port ",port c port q ""
        u port:(:"S"::" 0    11":9600) f i=1:1 r x:.2 e  q  ;discard any pending input.
        u 0 w !,"Modem control reset and DTR raised.",!,"Any residual input from previous sessions discarded"
        u port d showza(port,$za) ;show modem state.
        u 0 w !,"Resetting modem."
        u port:(:"S") w "ATZ",*13 r echo:3 e  u 0 w !,"no response to ATZ command" c port q ""
        r x,x,ok,y,y:1 s t1=$t i ok'="OK" u 0 w !,"OK not received following ATZ" c port q ""
        u 0 w " ",ok
        u 0 w !,"Dialing:  ATDT",number
        u port:(:"S") w "ATDT",number,*13 r echo:3 e  u 0 w !,"no echo to dial string" c port q ""
        r x,x ;get cr/lf
        r reply u 0 w " reply from modem:  ",reply
        i reply'?1"CONNECT".E c port q ""
        u 0 w !,"Setting COM port to modem control."
        u port:(:"S"::" 1")
        s connect=0 f i=1:1:4 d  q:connect  ;Wait for carrier detect.
        .u port:(:"S") s za=$za
        .u 0 w !,i,! d showza(port,za)
        .i za\32768#2 s connect=1 q
        .h 1
        .q
        i 'connect u 0 w !,"Not connected" c port q ""
        q port
        ;
showza(port,za) ;This formats and displays the value of $ZA (already obtained) for the port.
        n (port,za)
        u 0 w !,"$za for ",port," is ",za
        W !,"Modem Status:"
        w !,?5,"CTS = ",za\4096#2
        w !,?5,"DSR = ",za\8192#2
        w !,?5,"RING = ",za\16384#2
        w !,?5,"RLSD = ",za\32768#2
        s dtr=za\16777216#4
        w !,?5,"DTR = "
        w $s(dtr=0:"Off",dtr=1:"On",dtr=2:"DTR Handshaking enabled",1:"Invalid")," (Cache setting)"
        i za\65536=0 q
        W !,"Error status:"
        w !,?5,"BREAK = ",za\65536#2
        w !,?5,"FRAME = ",za\131072#2
        w !,?5,"IOE = ",za\262144#2
        w !,?5,"OVERRUN = ",za\524288#2
        w !,?5,"RXPARITY = ",za\1048576#2
        w !,?5,"TXFULL = ",za\2097152#2
        w !,?5,"TXHOLD = ",za\4194304#2
        q
        ;
        ;

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