MySQL More… 1

More on SQL In MySQL, the Information Schema is the “Catalog” in the SQL standard SQL has three components: Data definition Data manipulation Data control Granting access privileges 2

Special SQL statements CREATE DATABASE CLAIMS USE CLAIMS CREATE INDEX AGE ON CLAIMS-TABLE (AGE) GRANT SELECT ON CLAIMST TO DIANE CREATE VIEW BADCLAIMS … SHOW WARNINGS System variables, only some can be changed SELECT SET = TRUE Three kinds of system variables Session Global 3

Basic SQL statements SELECT - columns returned FROM – what tables used WHERE – conditions rows must meet GROUP BY - groups rows with equal column values HAVING – selects groups that meet conditions ORDER BY – sorts rows on column values LIMIT – how many rows are to be returned SET – creates variable definitions = (SELECT …) HANDLER – used to browse tables by rows HANDLER CLAIMST OPEN HANDLER CLAIMST READ FIRST 4

More SQL SELECT INTO FILE Puts data from a table into a file SELECT NAME FROM CLAIMST INTO OUTFILE ‘C:/CLAIMS.TXT’ LOAD DATA INFILE ‘C:/CLAIMS.TEXT’ INTO TABLE CLAIMST Takes data from a file and loads it into a table PKs and FKs creation CREATE TABLE CLAIMST (CLAIMID INTEGER NOT NULL, PLANID INTEGER NOT NULL, PRIMARY KEY (CLAIMID), FOREIGN KEY (PLANID) REFERENCES PLANS (PLANID)) 5

Domain types Tinyint Smallint Mediumint Integer Bigint Decimal Float Char Varchar Long varchar Longtext 6

More domain types Date Time Datetime Timestamp Year Blob Longblob Longvarbinary Geometric types for vectors and points and polygons Integer auto_increment 7

Table storage options Called “engines” MyISAM – default and fast Memory – for temporary tables that are small InnoDB – supports row locks Lots of others… 8

Code Stored procedures CREATE PROCEDURE NEW_POLICY BEGIN … END Can specify parameters Can create local variables CALL statement for running a stored procedure Can create cursors for stepping through rows INTO – for putting a value into a host variable Stored functions Can have input parameters but no output parameters They have RETURN statement in them Triggers We will look at these… Events – instead of set off by SQL execution, usually based on time 9