DroidDB Tip of the Month
DroidDB® Tip for December 2017
Unique Values
You may want to prevent a user from creating multiple records with the same value in a column. You can do this by doing this:
Say You wanted the column RECORD_ID to be unique. First, use FILE | MODIFY TABLE and create an index over the RECORD_ID column. Then, create an edit control connected to @var(35) (not RECORD_ID) that the user will use to specify the new record number.
Then, on your form, create a macro (EDIT | MACRO/EVENTS) called INSERT_RECORD:
- STEP 1: SORT BY sorting on RECORD_ID
- STEP 2: RECORD | SEARCH. For "Arg" use @var(35). Set "Skip ... if not found" to 2. Turn on the "Exact matches only" check box.
- STEP 3: MESSAGE BOX with the "Msg" set to 'Error: duplicate record id'
- STEP 4: RETURN FROM MACRO
- STEP 5: RECORD INSERT
- STEP 6: ASSIGN. For "Value" use @var(35). For "Col" use RECORD_ID
- STEP 7: RETURN FROM MACRO
Lastly, put a button on the form whose action is RUN MACRO that runs the INSERT_RECORD macro.
When the end user uses the form to create a new record, he should enter the RECORD_ID in the edit control connected to @var(35) and then press the button.
Top rated! I needed a solid database application development tool for mobile devices. I chose DroidDB for Android OS because it provided a way to get a strong product to market quickly. DroidDB is relational, gives me control over form layout, handles macros, and supports events. It works on all Android versions I have tried and is a great companion product to SYWARE’s VisualCE.
Mark Read, President
SyntegraTech, Inc.
