What are the field data types that cannot be sorted?

The field data type that cannot be sorted is: Remarks type. Unlike character-type data, the memo type has a fixed length and cannot exceed 254 characters. It is only used to define the field type when creating data. The memo-type field stores text data of variable length.

Memo data is divided into two categories: ordinary memo data and binary memo data (Memo Binary). Their functions are basically the same.

1. Ordinary memo type (Mome), referred to as memo type.

Unlike character data, which has a fixed length and cannot exceed 254 characters, it is only used to define field types when creating data. Note fields are used to store text data of variable length.

These text data can be either a short comment or a longer article. In fact, the memo field does not directly store the text itself (otherwise it would be no different from the character field), but only stores pointers to these texts. The content of the

text is stored in a remark file automatically generated by the system with the same name as the table and the extension: .DCT. Therefore, its length does not need to be very long. The system stipulates that its length is fixed at 4 digits.

2. The binary memo type (Memo Binary) is the same as the memo type, but its value will change when the code page changes. It is used for login scripts etc. in different countries. The reason is the same as for binary character types.

For more related knowledge, please visit:PHP Chinese website!

The above is the detailed content of What are the field data types that cannot be sorted?. For more information, please follow other related articles on the PHP Chinese website!