Difference between revisions of "SQLCHECKUNIQUE()"
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==Example== | ==Example== | ||
<code lang="recital"> | <code lang="recital"> | ||
| − | // Character | + | // Character cKeyField |
nCustIDUnique = sqlcheckunique("southwind!customers","customerid","'ALFKI'") | nCustIDUnique = sqlcheckunique("southwind!customers","customerid","'ALFKI'") | ||
| − | // Numeric | + | // Numeric cKeyField |
nEmpIDUnique = sqlcheckunique("southwind!employees","employeeid","3") | nEmpIDUnique = sqlcheckunique("southwind!employees","employeeid","3") | ||
</code> | </code> | ||
Revision as of 05:46, 24 April 2020
Contents
Purpose
Function to check whether a prospective column value is unique
Syntax
SQLCHECKUNIQUE(<cTable>, <cKeyField>, <cKeyValue>[, <lAllowblank>[, <lAllownull>]])
See Also
KEYLOOKUP(), LOOKUP(), RLOOKUP(), SEEK(), SET RELATION, SQLLOOKUP()
Description
The SQLCHECKUNIQUE() function checks the uniqueness of a prospective column value. The function will auto-detect if the specified table is a native Lianja table or a Virtual Table and act accordingly.
You should always provide a fully qualified database!table if your app is to work in Web/Mobile e.g "southwind!employees".
The numeric return value is 1 if the cKeyValue value already exists and 0 if it does not already exist in the cKeyField table column.
| Keywords | Description |
|---|---|
| cTable | Character expression to specify the table to be checked (native or Virtual Table). |
| cKeyField | Character expression to specify the column in the table to be checked. |
| cKeyValue | Character expression containing the value to be compared against cKeyField. If this is a character field then enclose it in quotes within quotes: " 'string' ". If it is a numeric then enclose it like this "1". |
| lAllowblank | Logical expression specifying whether blank values should be ignored. |
| lAllownull | Logical expression specifying whether null values should be ignored. |
Example
// Character cKeyField nCustIDUnique = sqlcheckunique("southwind!customers","customerid","'ALFKI'") // Numeric cKeyField nEmpIDUnique = sqlcheckunique("southwind!employees","employeeid","3")
