GlideRecord.isValid() — ServiceNow API

isValid()→ boolean

beginnerTested on Xanadu

What It Does

The isValid() method checks whether the GlideRecord object was successfully instantiated against a table that exists in the ServiceNow database schema. When you create a new GlideRecord with new GlideRecord('table_name'), the platform validates that the table exists and that you have at least read access to it.

Internally, ServiceNow performs a table metadata lookup during GlideRecord instantiation. The platform checks the sys_db_object table to verify the table exists, then validates your user role has the necessary table-level ACL permissions. If either check fails, the GlideRecord object enters an invalid state.

The method returns true for valid table instantiation and false when the table doesn't exist, has a typo in the name, or when you lack sufficient read permissions. It never returns null or undefined.

Edge cases include dynamic table names constructed at runtime, tables in different application scopes that aren't accessible, and tables that exist but are marked as inactive. The method also returns false for system tables that require elevated privileges, even if the table name is spelled correctly.

This method is unrelated to hasNext(), isValidRecord(), or whether any records exist in the table. A GlideRecord can be perfectly valid according to isValid() while containing zero records or pointing to an empty result set.

When to Use This

Use isValid() when working with dynamic table names, user-supplied input, or when building generic utilities that operate across multiple tables. This is essential in Script Includes that accept table names as parameters, or in Business Rules that might run against tables created by other applications or update sets.

Skip this method when working with known, hardcoded table names like incident or sys_user in standard ServiceNow implementations. Use hasNext() or isValidRecord() instead when you need to check whether records were found or whether the current record contains data.

⚠️

Common mistake: using isValid() to check if a query returned results. This method only validates the table exists, not whether any records were found.

Return Value

Returns a JavaScript boolean value—either true for successful table instantiation or false for invalid tables. The return value is set during GlideRecord construction and doesn't change based on subsequent queries or operations performed on the object.

The boolean return makes it safe for direct use in if statements without additional null checks. When false, attempting to perform database operations like query() or insert() on the GlideRecord will fail silently or throw exceptions depending on the operation.

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Platform Behavior & Side Effects

No Business Rules, Script Engines, or notifications fire when calling this method—it's purely a metadata check
Nothing is written to the database; this is a read-only validation against table metadata
Extremely fast performance—table metadata is cached at the application server level
Table-level ACLs are evaluated during instantiation, but record-level security is not checked
Identical behavior across all server-side contexts—Business Rules, Script Includes, and Scheduled Jobs
Result is determined at instantiation time and cannot change during the GlideRecord object's lifecycle
Does not count against any query limits or database connection pools

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Code Examples

Basic validation for dynamic table namesbasic

// Validate table exists before attempting operations
function getRecordCount(tableName) {
    var gr = new GlideRecord(tableName);
    
    if (!gr.isValid()) {
        gs.error('Invalid table name: ' + tableName);
        return -1;
    }
    
    gr.query();
    var count = gr.getRowCount();
    
    gs.info('Found ' + count + ' records in ' + tableName);
    return count;
}

// Safe to call with any string
getRecordCount('incident');     // Returns actual count
getRecordCount('fake_table');   // Returns -1, logs error

Essential pattern when accepting table names as parameters. The validation prevents runtime errors from invalid table operations.

Table validation in utility functionsintermediate

// Generic field value updater with table validation
var TableUtils = Class.create();
TableUtils.prototype = {
    updateFieldValue: function(tableName, sysId, fieldName, newValue) {
        var gr = new GlideRecord(tableName);
        
        // Validate table before proceeding
        if (!gr.isValid()) {
            throw new Error('Table does not exist or access denied: ' + tableName);
        }
        
        if (gr.get(sysId)) {
            gr.setValue(fieldName, newValue);
            gr.update();
            return true;
        }
        return false;
    },
    
    type: 'TableUtils'
};

Production-ready pattern for Script Includes that work across multiple tables. Prevents silent failures and provides clear error messages.

The classic mistake — checking for recordsadvanced

// WRONG: Using isValid() to check if records exist
var gr = new GlideRecord('incident');
gr.addQuery('state', 1);
gr.query();

if (gr.isValid()) {
    // This will ALWAYS be true for the incident table
    // Even if no records match the query
}

// CORRECT: Check if records were actually found
var gr2 = new GlideRecord('incident');
gr2.addQuery('state', 1);
gr2.query();

if (gr2.hasNext()) {
    // This correctly checks if the query returned results
    while (gr2.next()) {
        // Process each matching record
    }
}

The most common misuse of isValid() is trying to check query results. Use hasNext() or next() to verify that records were found.

Gotchas

isValid() returns true even if the table is empty or your query returns zero records—it only validates table existence.

The method can return false for tables that exist if you lack read permissions, making it appear the table doesn't exist.

Custom scoped application tables may return false when accessed from different application scopes, even with proper cross-scope privileges.

System tables like sys_rollback or sys_debug require elevated privileges and will return false for normal users regardless of spelling.

The validation result is cached at instantiation time—creating a new GlideRecord is the only way to recheck table validity.

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