SQL Server Database Recovery

Not everyone may be familiar with all the commands or terms used with Structured Query Language (SQL). SQL is a basic language that allows you to “speak” to a database and take out useful information. This page is a reference guide that will define certain commands and/or terms that you may come across to make your experience run a little more smoothly.

@: to run the specified command. This is similar to the ‘Start’ command.

alias: specifies names for the expressions selected by the view's query. The number of aliases must match the number of expressions selected by the view.

connect: to establish a connection to a database. It commits the current transaction to the database, disconnects the current username, and reconnects with the specified username.

data page: designed to store rows of user data in an SQL Server file.

data type: characteristic of a particular field.

ghost record: When rows are deleted from the leaf level of an index, they’re not immediately removed. Instead, they are marked as invalid and are called ghost records.

index: group of pointers that allows a DBMS (Database Management System) to find values in a certain field.

leaf level: refers to the leaf pages in a clustered or non-clustered index.

list: to display one or more lines of the SQL buffer.

null: specifies that a column can contain null values.

primary key: designates a column or combination of columns as the table’s primary key.

query: question you ask the database to request information, perform an action, or a calculation.

remark: when used at the beginning of a line, it means a comment in a command field. The comment ends at the end of the line. A line cannot contain both a comment and a command.

rollback: to undo work done in the current transaction.

spool: to store query results in an operating system file or send the file to a printer.

start: to execute the contents of a command file. Similar to the @ command.