revDatabaseColumnIsNull | ||||||||||
Type | function | |||||||||
Dictionary | LCS | |||||||||
Library | LiveCode Script | |||||||||
Syntax |
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Synonyms | revdb_columnisnull | |||||||||
Associations | database library | |||||||||
Summary | Returns true if the specified database field has a null value, false otherwise. | |||||||||
Introduced | 1.1.1 | |||||||||
Changes | The revDatabaseColumnIsNull synonym was added in version 2.0. | |||||||||
OS | mac, windows, linux, ios, android | |||||||||
Platforms | desktop, server, mobile | |||||||||
Parameters |
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Example |
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Values |
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Related | Control Structure: function Function: revDatabaseColumnNames, revDatabaseColumnLengths, revDatabaseColumnNumbered Glossary: LiveCode custom library, Standalone Application Settings, database field, record, return, standalone application Library: Database library | |||||||||
Security | disk, network | |||||||||
Description | Use the revDatabaseColumnIsNull function to find out whether one of the database fields in the current record is set to a value. A null value in a SQL database refers to a value that is unknown or not applicable. For example, if the price of an item in a product database has not yet been determined, its "Price" field is typically set to null. The null value is not zero: the item's price is not zero, but undetermined. The special null value allows the database to differentiate between an unknown value deliberately inserted, and a value of zero or a blank field. This means that if the data value of the database field is empty or zero, the revDatabaseColumnIsNull function returns false. It only returns true if the field's value is not set at all.
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Tags | database |