Administrator Guidelines for Password Security Database administrators should use the following guidelines to keep passwords secure. MySQL stores passwords for user accounts in the mysql.user table. Access to this table should never be granted to any nonadministrative accounts. Account passwords...
Assigning Anonymous Account Passwords The mysql commands in the following instructions include a -p option based on the assumption that you have set the root account passwords using the preceding instructions and must specify that password when connecting to the server. To assign passwords to th...
Backward Compatibility Considerations of backward compatibility only apply when using a recent version of InnoDB (the InnoDB Plugin, or MySQL 5.5 and higher with InnoDB 1.1) alongside an older one (MySQL 5.1 or earlier, with the built-in InnoDB r...
Calculating Visits Per Day The following example shows how you can use the bit group functions to calculate the number of days per month a user has visited a Web page. CREATE TABLE t1 (year YEAR(4), month INT(2) UNSIGNED ZEROFILL, day INT(2) UNSIGNED ZEROFILL); INSERT INTO t1 VALUES(2000,1,1),(...
Checking Whether Tables or Indexes Must Be Rebuilt A binary upgrade or downgrade is one that installs one version of MySQL “in place” over an existing version, without
Choosing a Distribution Format After choosing which version of MySQL to install, you should decide whether to use a binary distribution or a source distribution. In most cases, you should probably use a binary distribution, if one exists for you...
Clients and Tools: • MySQL includes several client and utility programs. These include both command-line programs such as mysqldump and mysqladmin, and graphical programs such as MySQL Workbench. • MySQL Server has built-in support for SQL sta...
Column Properties • Set a default value for a column: ALTER TABLE tbl ALTER COLUMN col SET DEFAULT literal or ALTER TABLE tbl ALTER COLUMN col DROP DEFAULT The default values for columns are stored in the .frm file for the table, not the InnoDB d...
Combining or Separating DDL Statements Before the introduction of online DDL, it was common practice to combine many DDL operations into a single ALTER TABLE statement. Because each ALTER TABLE statement involved copying and rebuilding the table, it was more efficient to make several changes to t...
Compatibility Check When a Table Is Opened When a table is first accessed, InnoDB (including some releases prior to InnoDB 1.0) checks that the file format of the tablespace in which the table is stored is fully supported. This check prevents cra...
