Is a field or set of fields in a record that is used to identify the record?

database: A collection of related information stored in a structured format. Database is sometimes used interchangeably with the term table. Technically, they�re different: A table is a single store of related information; a database can consist of one or more tables of information that are related in some way. For instance, you could track all the information about the students in a school in a students table. If you then created separate tables containing details about teachers, classes and classrooms, you could combine all four tables into a timetabling database. Such a multi-table database is called a relational database.

data entry: The process of getting information into a database, usually done by people typing it in by way of data-entry forms designed to simplify the process.

dbms: Database management system. A program which lets you manage information in databases. Lotus Approach, Microsoft Access and FileMaker Pro, for example, are all DBMSs, although the term is often shortened to �database�. So, the same term is used to apply to the program you use to organize your data and the actual data structure you create with that program.

field: Fields describe a single aspect of each member of a table. A student record, for instance, might contain a last name field, a first name field, a date of birth field and so on. All records have exactly the same structure, so they contain the same fields. The values in each field vary from record to record, of course. In some database systems, you�ll find fields referred to as attributes.

flat file: A database that consists of a single table. Lightweight database programs such as the database component in Microsoft Works are sometimes called �flat-file managers� (or list managers) because they can only handle single-table databases. More powerful programs, such as FileMaker Pro, Access, Approach and Paradox, can handle multi-table databases, and are called relational database managers, or RDBMSs.

foreign key: A key used in one table to represent the value of a primary key in a related table. While primary keys must contain unique values, foreign keys may have duplicates. For instance, if we use student ID as the primary key in a Students table (each student has a unique ID), we could use student ID as a foreign key in a StudentCourse table: as each student may do more than one course, the student ID field in the StudentCourse table (often shortened to StudentCourse.student ID) will hold duplicate values.

index: A summary table which lets you quickly look up the contents of any record in a table. Think of how you use an index to a book: as a quick jumping off point to finding full information about a subject. A database index works in a similar way. You can create an index on any field in a table. Say, for example, you have a customer table which contains customer numbers, names, addresses and other details. You can make indexes based on any information, such as the customers� customer number, last name + first name (a composite index based on more than one field), or postal code. Then, when you�re searching for a particular customer or group of customers, you can use the index to speed up the search. This increase in performance may not be noticeable in a table containing a hundred records; in a database of thousands of records it will be a blessing.

key field: You can sort and quickly retrieve information from a database by choosing one or more fields to act as keys. For instance, in a students table you could use a combination of the last name and first name fields (or perhaps last name, first name and birth dates to ensure you identify each student uniquely) as a key field. The database program will create an index containing just the key field contents. Using the index, you can quickly find any record by typing in the student�s name. The database will locate the correct entry in the index and then display the full record.

Key fields are also used in relational databases to maintain the structural integrity of your tables, helping you to avoid problems such as duplicate records and conflicting values in fields (see primary key and foreign key).

normalization: The process of structuring data to minimize duplication and inconsistencies. The process usually involves breaking down a single table into two or more tables and defining relationships between those tables. Normalization is usually done in stages, with each stage applying more rigorous rules to the types of information that can be stored in a table. While full adherence to normalization principles increases the efficiency of a particular database, the process can become so esoteric that you need a professional to create and understand the table design. Most people, when creating a database, don�t need to go beyond the third level of normalization, called third normal form.

primary key: A field that uniquely identifies a record in a table. In a students table, for instance, a key built from last name + first name might not give you a unique identifier (two or more Jane Does in the school, for example). To uniquely identify each student, you might add a special Student ID field to be used as the primary key.

query: A view of your data showing information from one or more tables. For instance, you could query the Students database asking "Show me the first and last names of the students who take both history and geography and have Alice Hernandez as their advisor" Such a query displays information from the Students table (firstname, lastname), Courses table (course description) and Advisor table (advisor name), using the keys (student ID, course ID, advisor ID) to find matching information.

rdbms: Relational database management system. A program which lets you manage structured information stored in tables and which can handle databases consisting of multiple tables.

record: A record contains all the information about a single �member� of a table. In a students table, each student�s details (name, date of birth, contact details, and so on) will be contained in its own record. Records are also known as tuples in technical relational database parlance.

relational database: A database consisting of more than one table. In a multi-table database, you not only need to define the structure of each table, you also need to define the associations between each table in order to link those tables correctly.

report: A form designed to print information from a database (either on the screen, to a file or directly to the printer).

SQL: Structured Query Language (pronounced sequel in the US; ess-queue-ell elsewhere). A computer language designed to organize and simplify the process of getting information out of a database in a usable form, and also used to reorganize data within databases. SQL is most often used on larger databases on minicomputers, mainframes and corporate servers.

table: A single store of related information. A table consists of records, and each record is made up of a number of fields. Just to totally confuse things, tables are sometimes called relations. You can think of the phone book as a table: It contains a record for each telephone subscriber, and each subscriber�s details are contained in three fields � name, address and telephone.

Is a field or set of fields in a record that identifies the record?

What is a set of fields and records?

What is a field in a record?

What is identified as a field in database?