Delete null records in the Access dictionary. Author: Tao Net Source: Tao net note: reprinted please indicate the source with a zero-length character to indicate that no data exists. to indicate that no data exists in the MicrosoftAccess database, you can
Source: Taotao
Note: Please indicate the source for reprinting.
Zero-length characters are used to indicate that no data exists.
To indicate that no data exists in the Microsoft Access database, you can enter a zero-length string (zero-length string: non-character string) in the "text" or "remarks" field. You can use a zero-length string to indicate that this field has no value. You can enter a zero-length string by double quotation marks ("") without spaces between the two strings ("").). In the Microsoft Access project connected to the Microsoft SQL Server database (Microsoft Access Project: an Access file that is connected to the Microsoft SQL Server database and used to create client/Server applications. The project file does not contain any data or data-defined objects (such as tables or views ).) The data type (data type: determines the field features of the data type that a field can possess. Data types include Boolean, Integer, Long, Currency, Single, Double, Date, String, and Variant (default ).) Enter a zero-length string for the varchar or nvarchar field.
Open a data table ("Data Table" view: displays a window from a table, form, query, view, or stored procedure in the row/column format. In the data table view, you can edit fields, add and delete data, and search for data .), Or in the form View (form View: A display form to display or accept data. The form view is the main method for adding and modifying table data. You can also change the form design in this view .) Open the form.
To enter a zero-length string in a field, type double quotation marks ("") without spaces in the middle ("").
This field is still a zero-length string even when it is moved to another field or object.
Difference between a Null value and a zero-length string (MDB)
/* Comment the information in this topic only applies to Microsoft Access database (. mdb ). */
Check that Null is contained (Null: can be input in a field or used for expressions and queries to indicate lost or unknown data. In Visual Basic, the Null keyword indicates the Null value. Some fields (such as primary key fields) cannot contain Null values .) Value and zero-length string (zero-length string: string that does not contain characters. You can use a zero-length string to indicate that this field has no value. You can enter a zero-length string by double quotation marks ("") without spaces between the two strings ("").) The fields are the same and have no value. However, expressions (expressions: arithmetic or logical operators, constants, functions and field names, controls, and attributes can be used in any combination. the calculation result is a single value. Expressions can perform computation, Operation characters, or test data .) To distinguish between Null and zero-length strings.
In the design View (Design View: displays the design windows for database objects (including tables, queries, forms, macros, and data access pages. In the design view, you can create database objects and modify the design of existing database objects .) Open the form, report, or data access page.
Sources Source: Tao net note: reprinted please indicate the source with a zero-length character to indicate that there is no data in the Microsoft Access database, you can in the "text...
