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Microsoft Access 2007 Tutorials for beginners |
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Welcome to MS Tips and Tricks |
Welcome to MS Tips and Tricks -
You are at the right place if you need tutorials for beginners - Online Microsoft Access tutorials for beginners, covering the following categories
- Databases, Customization, Table, Forms, Queries, Reports, etc.,
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Microsoft Access Tips and Tricks for beginners |
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Written by Ravi Prakash
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Friday, 22 June 2007
Category MS Access 2007 - Tables.
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| General Information |
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What is a table
Tips on creating tables
Access 2007 data types
Steps to create a table from scratch
Import Data: appending in an existing table
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| What is a table? |
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Relational databases are constituted by one or more tables than contain the information in an organized form. Databases usually contain more than one table
and each one will have a fixed number of fields. |
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The tables are made up by two structures: |
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 | Field: It corresponds to the name of the column. It must be unique and besides to have a data type associate. |
| | Record: It corresponds to each row that composes the table. There the data and the registries are composed. |
| Each table in your database should hold the information on one subject. You might think of a subject as a collection of related information with common characteristics. For example, a Book table will hold information about books like: Title, Author, pages quantity and so on. |
 | The name of each table must be unique in the database. |
| | Each field name must be unique within a table. |
| | Table names should normally be plural. |
| | Table and field names should be as brief as possible but also should clearly identify the subject of the table or the data in the field. |
| | Avoid abbreviations and acronyms if you can as they can be cryptic to another user of the database. |
| | Some designers prefer to follow a naming convention that includes a tag that identifies each object. |
| When setting up table´s fields, you will find the follows available data types: |
| Text | Alphanumeric characters. | Up to 255 characters. |
| Use for text, or text and numbers that are not used in calculations (for example, a product ID). | |
| Memo | Alphanumeric characters (longer than 255 characters in length) or text with rich text formatting. | Up to 1 gigabyte of characters, or 2 gigabytes of storage (2 bytes per character), of which you can display 65,535 characters in a control. |
| Use for text greater than 255 characters in length, or for text that uses rich text formatting. Notes, lengthy descriptions, and paragraphs with formatting such as bold or italics are good examples of where you would use a Memo field. | |
| Number | Numeric values (integers or fractional values). | 1, 2, 4, or 8 bytes, or 16 bytes when used for replication ID. |
| Use for storing numbers to be used in calculations, except for monetary values (use the Currency for data type for monetary values). | |
| Date/Time | Dates and times. | 8 bytes. |
| Use for storing date/time values. Note that each value stored includes both a date component and a time component. | |
| Currency | Monetary values. | 8 bytes. |
| Use for storing monetary values (currency). | |
| AutoNumber | A unique numeric value that Office Access 2007 automatically inserts when a record is added. | 4 bytes or 16 bytes when used for replication ID. |
| Use for generating unique values that can be used as a primary key. Note that AutoNumber fields can be incremented. | |
| sequentially, by a specified increment, or chosen randomly. | |
| Yes/No | Boolean values. | 1 bit (8 bits = 1 byte). |
| Use for True/False fields that can hold one of two possible values: Yes/No or True/False, for example. | |
| OLE Object | OLE objects or other binary data. | Up to 1 gigabyte. |
| Use for storing OLE objects from other Microsoft Windows applications. | |
| Attachment | Pictures, Images, Binary files, Office files. | For compressed attachments, 2 gigabytes. For uncompressed attachments, approximately 700k, depending on the degree to which the attachment can be compressed. |
| This is the preferred data type for storing digital images and any type of binary file. | |
| Hyperlink | Hyperlinks. | Up to 1 gigabyte of characters, or 2 gigabytes of storage (2 bytes per character), of which you can display 65,535 characters in a control. |
| Use for storing hyperlinks to provide single-click access to Web pages through a URL (Uniform Resource Locator) or files through a name in UNC (universal naming convention) format. You can also link to Access objects stored in a database. | |
| Lookup Wizard | Not actually a data type; instead, this invokes the Lookup Wizard. | Table or query based: The size of the bound column. |
| Use to start the Lookup Wizard so you can create a field that uses a combo box to look up a value in another table, query or list of values. | Value based: The size of the Text field used to store the value. |
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