SQL syntax and SQL statement reference and Recordset object in ASP

SQL syntax
DB2 provides query language SQL (Structured query Language) of the related database, which is a very colloquial, easy to learn and understandable syntax. This language is almost always required by every database system to represent connected operations, including the definition of data (DDL) and Data Processing (DML). SQL originally spelled sequel, the language of the prototype of "System R" in the name of the IBM San Jose Laboratory completed, through the internal IBM and many other usability and efficiency testing, the results are quite satisfactory, and decided to develop the system R technology based on IBM's products. And the American National Standards Institute (ANSI) and the International Organization for Standardization (ISO) in 1987 follow an almost IBM-SQL based standard related data language definition.
I. Data definition DDL (data definition Language)
Data-setting language refers to the language defined in the format and form of data, he is the first to be set up when each database is to be established, what is the form of data, the form of a field key, tables and tables of the relationship between the reference and so on, are in the beginning must be planned.
1, build the form:
CREATE TABLE table_name (
Column1 DATATYPE [NOT NULL] [NOT NULL PRIMARY KEY],
Column2 DATATYPE [Not NULL],
... ）
Description
DATATYPE--is the format of the data, as detailed in the table.
NUT null--Can you allow the data to be empty (no data has been filled in yet).
PRIMARY Key--is the primary key for this table.
2. Change the form
ALTER TABLE table_name
ADD COLUMN column_name DATATYPE
Description: Adds a field (without deleting a field's syntax.)
ALTER TABLE table_name
ADD PRIMARY KEY (column_name)
Description: Change the definition of a table to set a field as the primary key.
ALTER TABLE table_name
DROP PRIMARY KEY (column_name)
Description: Delete the definition of the primary key.
3, the establishment of the index
CREATE INDEX index_name on table_name (column_name)
Description: Index The field of a table to increase the speed of the query.
4, delete
DROP table_name
DROP index_name
Second, the data form datatypes
smallint
A 16-bit integer.
Interger
A 32-bit integer.
Decimal (P,s)
P exact value and s size decimal integer, the exact value P refers to the total number of values (digits) size value, S is the decimal
There are several numbers after the point. If not specifically specified, the system is set to p=5; S=0.
Float
A 32-bit real number.
Double
A 64-bit real number.
CHAR (n)
N-length string, n cannot exceed 254.