The MySQL server maintains many system variables that configure its operation. Each system variable has a default value. System variables can be set at server startup using options on the command line or in an option file. Most of them can be changed dynamically at runtime using the Show At runtime, setting a global system variable value requires the
Some system variables control the size of buffers or caches. For a given buffer, the server might need to allocate internal data structures. These structures typically are allocated from the total memory allocated to the buffer, and the amount of space required might be platform dependent. This means that when you assign a value to a system variable that controls a buffer size, the amount of space actually available might differ from the value assigned. In some cases, the amount might be less than the value assigned. It is also possible for the server to adjust a value upward. For example, if you assign a value of 0 to a variable for which the minimal value is 1024, the server sets the value to 1024. Values for buffer sizes, lengths, and stack sizes are given in bytes unless otherwise specified. Some system variables take file name values. Unless otherwise specified, the default file location is the data directory if the value is a relative path name. To specify the location explicitly, use an absolute path name. Suppose that the data
directory is
What are examples of SQL injection attacks?Some common SQL injection examples include: Retrieving hidden data, where you can modify an SQL query to return additional results. Subverting application logic, where you can change a query to interfere with the application's logic. UNION attacks, where you can retrieve data from different database tables.
Which of the following should you avoid when constructing SQL statements?You should not build your SQL statements with string concatenation of user input.
What are the two types of SQL injection attacks?Types of SQL injection attacks. Unsanitized Input. ... . Blind SQL Injection. ... . Out-of-Band Injection.. What causes SQL injection vulnerabilities?The three root causes of SQL injection vulnerabilities are the combining of data and code in dynamic SQL statement, error revealation, and the insufficient input validation.
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