Use a Database Device

You can use a database device to do the following:

Write dBase Records

To write data to a database device, first append a record to the end of the device, then add data to the fields of the record. For a dBASE database, the DevAppend() function appends the record, and the DevSetField() function writes data to a field. The following function writes a recipe record to a device:

FUNCTION

WriteRecipeData(INT hDevice, STRING sName, INT Water, INT Sugar,

T Flour, INT Salt, INT Yeast, INT Milk)

DevAppend(hDevice);

DevSetField(hDevice, "NAME", sName);

DevSetField(hDevice, "WATER", IntToStr(Water));

DevSetField(hDevice, "SUGAR", IntToStr(Sugar));

DevSetField(hDevice, "FLOUR", IntToStr(Flour));

DevSetField(hDevice, "SALT", IntToStr(Salt));

DevSetField(hDevice, "YEAST", IntToStr(Yeast));

DevSetField(hDevice, "MILK", IntToStr(Milk));

END

Write SQL Records

To use an SQL device in Plant SCADA, you cannot use every the Cicode Device function; you can only use the following functions:

To write Plant SCADA data to an SQL database, use the DevWrite() function, but you need to add a new record and write to fields in the new record. No data is written to the database if you do not write to all fields.

For example:

FUNCTION

WriteRecipeData(INT hDevice, STRING sName, INT Water, INT Sugar,

INT Flour, INT Salt, INT Yeast, INT Milk)

DevWrite(hDevice, sName);
DevWrite(hDevice, Water);
DevWrite(hDevice, Sugar);
DevWrite(hDevice, Flour);
DevWrite(hDevice, Salt);
DevWrite(hDevice, Yeast);
DevWrite(hDevice, Milk);

END

The following functions return error 267 (File mode is invalid) when the device type is SQL:

The follow function returns error 263 (Cannot read file) when the device type is SQL:

The following functions return error -1 when the device type is SQL:

Locate and Read Database Records

To read data from a dBASE or SQL database device, use the DevFind() function to locate the record, and then the DevGetField() function to read each field:

FUNCTION

GetRecipe(STRING sName)

INT hDev;

hDev = DevOpen("Recipe");

IF hDev >= 0 THEN

IF DevFind(hDev, sName, "NAME") = 0 THEN

PLC_Water = DevGetField(hDev, "WATER");

PLC_Sugar = DevGetField(hDev, "SUGAR");

PLC_Flour = DevGetField(hDev, "FLOUR");

PLC_Salt = DevGetField(hDev, "SALT");

PLC_Yeast = DevGetField(hDev, "YEAST");

PLC_Milk = DevGetField(hDev, "MILK");

ELSE

DspError("Cannot Find Recipe " + sName);

END

DevClose(hDev);

ELSE

DspError("Cannot open recipe database");

END

END

Delete Records

You can delete dBASE records with the DevDelete() function. The following Cicode function deletes records from a dBASE device:

FUNCTION DeleteRecords(INT hDev)

WHILE NOT DevEOF(hDev) DO

DevDelete(hDev);

DevNext(hDev);

END

END

To delete every record from a dBASE database, use the DevZap() function:

FUNCTION DeleteRecords(INT hDev)

DevZap(hDev);

END

To delete records from an SQL database, use the Cicode SQL functions.

To open a database device or devices:

Use the DevOpen() function. this function returns an integer handle to identify each device, as in the following example:

INT hRecipe;
hRecipe = DevOpen("Recipe");

When you are finished with a device, close it to free Cicode system resources by using the DevClose() function. For example:

DevClose(hRecipe);

See Also

Use Device History Files