Create (SQL)
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A CREATE statement in SQL creates an object inside of a relational database management system (RDBMS). The types of objects that can be created depends on which RDBMS is being used, but most support the creation TABLEs, INDEXes, USERs, and DATABASEs. Some systems (such as PostgreSQL) allow CREATE and other DDL commands to occur inside of a transaction and thus be rolled back.
[edit] CREATE TABLE
Perhaps the most common CREATE command is the CREATE TABLE command. The typical usage is:
CREATE [TEMP[ORARY]] TABLE [table name] ( [column definitions] ) [table parameters].
Column Definitions: A comma-separated list consisting of any of the following
- Column definition: [column name] [data type] {NULL | NOT NULL} {column options}
- Primary key definition: PRIMARY KEY ( [comma separated column list] )
- CONSTRAINTS: {CONSTRAINT} [constraint definition]
- RDBMS specific functionality
For example, the command to create a table named employees with a few sample columns would be:
CREATE TABLE employees (
id INTEGER PRIMARY KEY,
first_name CHAR(50) null,
last_name CHAR(75) not null,
date_of_birth DATE null
);
