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In the relational model of databases, a primary key is a designated attribute that can reliably identify and distinguish between each individual record in a table.The database creator can choose an existing unique attribute or combination of attributes from the table (a natural key) to act as its primary key, or create a new attribute containing a unique ID that exists solely for this purpose ...
The columns in a candidate key are called prime attributes, [3] and a column that does not occur in any candidate key is called a non-prime attribute. Every relation without NULL values will have at least one candidate key: Since there cannot be duplicate rows, the set of all columns is a superkey, and if that isn't minimal, some subset of that ...
After right-clicking on a folder one can open a command-line prompt in that folder. Windows Explorer also contains modifications in the visualization of files on a computer. A new addition to Windows Explorer in Vista and Server 2008 is the details pane, which displays metadata and information relating to the currently selected file or folder.
A command-line interface is a means of interacting with a computer program where the user issues commands to the program by typing in successive lines of text (command lines). MySQL ships with many command line tools, from which the main interface is the mysql client. [123] [124]
MySQL Workbench is the first MySQL family of products that offer two different editions - an open source and a proprietary edition. [31] The "Community Edition" is a full featured product that is not crippled in any way. Being the foundation for all other editions it will benefit from all future development efforts.
Tab ↹ (enabled by default in Windows XP and later) Tab ↹: Tab ↹ (usually once) Esc (usually twice) Paste contents of clipboard at cursor: Alt+Space then E [notes 10] then P: Ctrl+V: ⇧ Shift+Ins: Scroll window up ⇧ Shift+PageUp (may not work in some versions of Windows XP) PageUp: ⇧ Shift+PageUp: Scroll window down
Using a SELECT statement after the INSERT statement with a database-specific function that returns the generated primary key for the most recently inserted row. For example, LAST_INSERT_ID() for MySQL. Using a unique combination of elements from the original SQL INSERT in a subsequent SELECT statement.
One of those keys per table may be designated the primary key; other keys are called alternate keys. Any key may consist of one or more attributes. For example, a Social Security Number might be a single attribute key for an employee; a combination of flight number and date might be a key consisting of two attributes for a scheduled flight.