Database -- add field statement, -- field statement

Database -- add field statement, -- field statement



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Generic Syntax: alter table [table name] add [field name] field property default value is an optional parameter

Instance:

Alter table class table 2 add COLUMN Group int 0

The following example may be true for column

Alter table [table name] add field name smallint default 0 add numeric field, integer, default value 0

Alter table [table name] add field name int default 0 add numeric field, long integer, default value 0

Alter table [table name] add field name single default 0 add numeric field, single precision type, default value is 0

Alter table [table name] add field name double default 0 add numeric field, double precision type, default value is 0

Alter table [table name] add field name Tinyint default 0 add numeric field, byte type, default value is 0

Alter table [table name] add field name text [null] add remarks field, [null] optional parameter

Alter table [table name] add field name memo [null] add remarks field, [null] optional parameter

Alter table [table name] add field name varchar (N) [null] Increase the variable-length text field size to N (1 ~ 255)

Alter table [table name] add field name char [null] increase fixed length text type field size to 255

Alter table [table name] add field name Datetime default function adds a date field, where the function can be now (), date (), etc., indicating the default value

(The above are the most common and there are other attributes. You can refer to the following data type description)

Delete field: alter table [table name] drop field name

Modify the size of a variable-length text field: alter table [table name] alter field name varchar (N)

Delete table: drop table [table name]

Create a table:

SQL = "CREATE TABLE [TABLE name] ([Field 1, and set it as the PRIMARY KEY] int IDENTITY (1, 1) NOT NULL CONSTRAINT PrimaryKey PRIMARY KEY ,"&

"[Field 2] varchar (50 ),"&

"[Field 3] single default 0 ,"&

"[Field 4] varchar (100) null ,"&

"[Field 5] smallint default 0 ,"&

"[Field 6] int default 0 ,"&

"[Field 7] date default date (),"&

"[Field 8] int default 1 )"

Conn.exe cute SQL

Null indicates that the field can be zero-length.

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