Create Table

create table statement is used to create a new table. Here is the syntax:

  create table tablename
    (
     column1 data type(size),
     column2 data type(size), 
     column3 data type(size)
    );

For example:

  create table members
    (
     userId varchar(25),
     user   varchar(20),
     pass   varchar(20),
     page   varchar(50)
    );

Data types specify what the type of data can be for that particular column. Here are the most common Data types:

char(size) ---------Fixed-length character string. Size is specified in parenthesis. Max 255 bytes.
varchar(size) ------Variable-length character string. Max size is specified in parenthesis.
number(size) ------Number value with a max number of column digits specified in parenthesis.
date --------------Date value
number(size,d) ---Number value with a maximum number of digits of "size" total, with a maximum number of "d" digits to the right of the decimal.

Alter Table

We can add a column to a table by using the key words alter table and add:

  alter table members add logoLink(50);

This statement add a column named logoLink to the members table.

Drop Table

To delete a table, we use the key words drop table:

  drop table members;

If you execute this statement, the table named members will be permanently removed.

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