Introduction to Tables

Introduction to Data Fields   A Database From Scratch In the previous lesson, we saw that you could create a database using one of the available templates. This approach provides you with readily made objects you can directly start using. Another technique consists of creating an empty database that has no built-in object. Starting a database from scratch allows you to create and add its different objects when necessary. The main advantage of this approach is that you will exercise as much control as possible on your database because you will be creating all of your objects. The disadvantage is that you will miss that primary layout that the templates offer. Creating a database from scratch simply means starting from a blank database and adding the different components. Of course, after learning how to perform some changes, you will be able to modify some aspects of a database, whether created from a template or started from scratch. To create a database from scratch, if you are just launching Microsoft Access, in the left section, you can click Featuring. Then, in the main section in the middle, click Blank Database, give a name in the File Name text box, and click Create. Practical Learning: Creating a Blank Database Start Microsoft Access To start a new database, in the File section and under Available Templates, make sure Blank Database is selected or click it. In the right section, set the File Name to Clarksville Ice Cream Click Create to create the new database file Introduction to Tables Imagine you create a list of people. The list can be started with names as follows: Bill, James, Hermine, and Khan. This type of list is considered one-dimensional because all of its items fit in one category. In order to create a more detailed list, you may want to include these people's email addresses and probably other related information. If you include these additional pieces of information in the same category, the list may become confusing. To arrange the list, you would divide it in categories. Here is an example: Name Email Address Phone Number Relationship Bill bill@yahoo.com   Friend James jamesemail.com (102)399-2893   Hermine   (101) 447-8384 Cousin Khan @Khan.com     This type of display allows you to refer to a piece of information by its category. This is the basis of a table. A table is a two-dimensional list of items so that the items are arranged by categories. A complete or incomplete series of items that represent each category is called a record. Therefore, a table can be represented as follows: In database development, a category is represented as a column. Sometimes it is also called a field. A record is represented as a row. Database Object and Fields A field is an object used to host, hold, or store a piece of information of a database. Before such an object can perform its function, it must first be created. In the strict sense, the most important or the most regularly used fields of a database are created on a table, but tables may not be the friendliest windows to present to a user for data entry. For this reason, fields can and should also be created on other windows. The process of making a field available depends on the type of object it will reside on and probably how the field will be used. This leads to two categories of fields: those that can receive or store information and those that can only present or display it. All fields of a table, especially in Microsoft Access, are created to store data. On the other hand, fields on almost all of the other objects (queries, forms, reports) can be made of combinations of already existing fields of a table, or they can be created independently of any existing or non-existing data. Table Layout   The Table's Tab A table is presented as a rectangular window represented in the middle of the screen with a tab. As an option, you can remove the tabs and let the tables display without them. To do this, you can click File and click Options. In the left frame, click Current Database and, in the right frame, in the Document Window Options section, click the Tabbed Documents radio button and remove the check mark on the Display Document Tabs check box: After making the selection, you can click OK. You will be asked to close and reopen the database: Which you should do. On the left side of its top section, a table presents an icon . The table icon provides a menu you can access when you right-click. The menu allows you to save or change the view of the table. When a table displays with a tab, the extreme right section of the tab(s) shows a close button you can click to close the table. The Table System Buttons In Microsoft Office Access 2010, by default, a table in Datasheet View is represented with a tab, which prevents the user from moving it around. If you want, you can make the tables of a database appear as single documents. To do this, open the Access Options dialog box from the File category. In the left frame, click Current Database. Under Document Window Options in the right frame, click the Overlapping Windows radio button:  When you click OK, you will be asked to close and reopen the database (which you should do). A Table as a Datasheet Although a table is primarily recognized as an arranged list of columns and rows, each column and each row intersect to create a rectangular box called a cell: The cell is actually the object that holds data of a table. A cell holds only one piece of information. The database developer decides what type of information would go into a cell but the user types that information. Based on its arrangement of cells, a table is said to display in a datasheet layout or simply a datasheet (because its view is made of cells). The Scroll Bars If you start entering data into a table and there are more records than the height of the table can display, the table would be equipped with a vertical scroll bar. The vertical scroll bar would allow you to move up and down on the datasheet. This is useful if/when a table has more records than can be displayed all at once, and this will happen regularly. In the same way, if a table contains one or more records than the width of the table can display, the table would be equipped with a horizontal scroll bar: The presence or absence of one or both scroll bars is automatically managed by the operating system and you should not be concerned with the management of the scroll bars. At the same time, if your users need to use a table, they know how to use a scroll bar. Table Navigation Buttons The lower left side of the table is made of four buttons used to navigate the table, one button used to create a new record, and a text box. Each button plays a specific role: Button Name Role First Record Allows moving to the first record of the table Previous Record Allows you to move one record back (if there is one) from the current record Current Record Displays the number representing the current record out of the total number of records Next Record Allows moving you one record ahead Last Record Allows moving you to the last record of the table  New (Blank) Record Used to enter a new record on the table   Introduction to Table Creation   Table Creation To have a table as part of your database, you must create it. You have various options. If you create a database using one of the local templates, it would provide you with a few tables that you can start using. Otherwise, to create a table, on the Ribbon, you can click Create. In the Tables section, click Table. This would cause the Ribbon to switch to a section labeled Fields: From the Fields tab, you can make selections. Practical Learning: Creating a Table Open the Rockville Technologies database created in the previous lesson On the Ribbon, click Create In the Tables section, click Table The Name of a Table Like everything that is part of a database, a table must have a name that can be used to refer to that object throughout the database and in other files that can be linked to the table. There are two main ways you can specify the name of a table, either when you save it for the first time or if you decide to rename it. To save a table you have just created: You can click File and click Save You can right-click the Table_X (such as Table1) tab and click Save You can press Ctrl + S You can start closing the table. You would be prompted to save the change (if its structure has been changed from the structure it had before it was opened) If a table has not been saved before, you will be asked to provide a name for the table. A table can have almost any name: Employees, 2&&4DG, Pestes, verTT#@tg, etc. Because you and your users should be able to easily identify a table, there are suggestions you should follow when naming it: The name of a table should reflect the kind of data it is holding You can name a table with a few words, with spaces You can use a prefix that identifies the table as such, a table. The name of a table would be preceded with tbl. If the name includes one word, such as Musicians, you can give the table a name like tblMusicians, another name would be tblStudents If the name of the table reflects a combination of words, such as Bank Accounts or Students Academic Numbers, you should start each new word with an uppercase. Here are examples: tblBankAccounts, tblStudentAcademicNumbers, tblMemberRegistrations. In our lessons, we will not use the convention of prefixing the name of a database object with three letters. For example, the names of tables will not start with tbl. We came to this decision because most other database environments, including Microsoft SQL Server, do not suggest this rule. Although the lack of this rule may create some confusion, because you will end up having a table and a form with the same name, we will strive to explicitly state what object type we are referring to. For example, we will avoid writing, "Open Employees" or "Open the Employees object". Instead, we will usually state, "Open the Employees table".   Practical Learning: Saving a Table To save the table, right-click Table1 and click Save Type Corporate Items as the name of the table Click OK To close the table, click its Close button Table Management   The Tables in the Navigation Pane Because the table is the primary object of a database, when you create a table and save it by giving it a name, Microsoft Access creates a section labeled Tables in the Navigation Pane and displays the name of thew new table in that section. In the same way, you can have as many tables as possible in the Tables section. Here is an example: As we will see in the next lesson, you can create other object and they will have their sections. Each section is expandable and collapsible. To expand a section, click the header of that section. To the same to collapse a section. Opening a Table The most regular operations you will perform on a table require that you open it first. To open a table, first locate it in the Navigation Pane then: You can double-click the table You can right-click the table and click Open Any of these actions causes the table to display in Datasheet View in the central area of the screen. In the same way, you can open as many tables as necessary. Closing a Table After using a table, you can close it. Before closing a table, first select its tab. Then, to close a table: You can click the close button on the right side of the tabs You can press Ctrl + Shift + F4 Selecting a Table In order to use a table, some operations require that you (or rather the user) first select(s) it: To select a table in the Navigation Pane, simply click it If you had opened many tables and they are displaying in the main area of the screen, to select one, click its tab or its title bar If you have many tables displaying in the main area of the screen, you can press Ctrl + F6 continuously to switch from one table to the next until the desired one displays Renaming a Table We saw that, when or after creating a table, you must save it to make it part of your database. When saving it for the first time, you must give it a name. If the name of a table is not appropriate, you can change it. To rename a table, in the Navigation Pane, you can right-click the name of the table and click Rename. Practical Learning: Renaming a Table In the Navigation Pane window, right-click the Corporate Items table and click Rename Type Employees Resources as the new name of the table Press Enter Deleting a Table If you have a table you don't need anymore, you can remove it from your database. Because you cannot delete a table if it is opened, you must first close it. To remove a table from your database: In the Navigation Pane, right-click the table and click Delete In the Navigation Pane, click the table to select it. Then, on the Ribbon, click Home. In the Record section, click Delete In the Navigation Pane, click the table to select it and press Delete In each case, you will receive a warning to confirm what you want to do. It is important to know that if you delete a table, because it is not a file, it does not go into the Recycle Bin: it is lost, including its records. Therefore, before deleting a table, make sure you really want to get rid of it. When in doubt, do not delete it. Practical Learning: Deleting a Table In the Navigation Pane, right-click the Employees Resources table Click Delete Read the warning of the message box and click Yes

 

Tables Columns in the Datasheet View   Creating a Column Although we did not mention it so far, a table does not exist without a column. Put it another way, a table must have at least one column in order to have meaning. This also means that, in order to create a table, it must actually have at least one column. If you start a table in Datasheet View, Microsoft Access creates and gives it one default column. Once a table displays in Datasheet View, you can start entering data into its cells. If you do this, whenever you enter data under a column, that column receives an incremental name: the first column on the right side of ID would be named Field1, the second would be Field2, and so on. These would be insignificant and can even be confusing. Fortunately, you can give meaningful names to the columns of your table. Naming a Column A column can have almost any name: "Book Title", "DG$5@H", "This Is The Book Title", "R8%%DW$4", etc. Some columns will have only tinny data, like a person's age, the number of books in an office, a person's middle initial, etc. It may not be a good idea to give them a name that would take too much space. To name a field, first figure out what the data in the category will be made of. If you are planning to enter employees' salaries in a field, you can just call it Salary. If you want to specify employees's names by first name, middle name, and last name, you can use such column names and make them distinct. In this case, you could name the first column as first name, the last name would be called last name. Although you can use one word names, some people might be confused. The suggestion is to distinguish wherever a new English (or the language you are using to design your database) name starts in the field name, by using a starting uppercase. Instead of firstname or first name, you can use FirstName or First Name. Instead of fullname or full name, you can use FullName or Full Name. Before changing the name of a column: You can double-click its header You can right-click a column and click Rename Column When any cell under a column has focus, on the Ribbon, you can first click Datasheet. Then, in the Fields & Columns section, click Rename Column.  Any of these actions would put the name of the column into edit mode. You can then type the new desired name or change the existing name. Using a Sample Field When you start a table in the Datasheet View, the Ribbon becomes equipped with a new tab labeled Fields. The sample fields and their configurations are distributed in various sections. One of the sections of the Fields tab is named Add & Delete: Microsoft Access provides many pre-configured fields you can add to your table. These ready-made sample columns are referred to as a Field Templates. To use a field template, while the table is displaying in Datasheet View: Click or right-click the header of a column. This would bring a menu from where you can select an option On the table, click the header column or a cell under the column. In the Add & Delete section of the Fields tab of the Ribbon, click the type of field you want In the Add & Delete section of the Ribbon, click More Fields to display a list and click an option from that menu Practical Learning: Using Fields Click File In the list of previously opened databases, click Clarksville Ice Cream To create a new table, on the Ribbon, click Create In the Tables section, click Table Click Click To Add and click Text When it is highlighted, type Order Date and press Enter As the menu displays in the next column, click Text Type Order Time and press Enter As the menu appears in the next column header, click Text Type Container and press Tab Press Esc Close the table When asked whether you want to save it, click Yes Type Customers Orders as the name of the table Click OK To start a new table, on the Ribbon, click Create Click Table In the Add & Delete section, click Text Type Manufacturer and press Enter Press Esc In the Add & Delete section, click Text Type Model and press Enter Press Esc In the Add & Delete section, click Date & Time Type Acquired Date and press Enter Press Esc In the Add & Delete section, click Currency Type Purchase Price and press Enter Press Esc In the Add & Delete section, click Text Type Company and press Enter Press Esc Right-click Table1 and click Save Set the name to Company Assets Click OK Click its Close button Columns Maintenance in the Datasheet View   Importing a Table and its Columns Although a column completely depends on a table, both objects are closely related when it comes to their maintenance. In other words, the maintenance performed on one object can directly affect the other. For example, you can import a table from a text file or from another application. A table cannot exist without at least one column. Selecting a Column Some operations will require that you select a column but it depends on the operation you want to perform. In some cases, when any cell under a column has focus (for example if the caret is blinking in a cell of a column), the column is considered to be selected. Otherwise: To select one column, position the mouse on its name until the cursor points down and then click To select columns in a range, click and hold your mouse on one of them, then drag to the left or to the right to cover the other desired column or columns. When all desired columns are highlighted, release the mouse To select a range of columns, click one column that will be at one end, press and hold Shift, then click the column that will be at the other end, and release Shift Changing the Width of a Column If you create a table using one of the Table Templates or if you get a table from a Database Template, the columns of the tables are wide enough to show their names. If  you create a table from scratch in the Datasheet View, Microsoft Access assigns it a default width. That width can appear to be too narrow or too wide. For example, when data exceeds the regular width of a column, part of the information would be hidden. If a particular column contains data that you want to display at all times, you can enlarge the column. On the other hand, if a column displays tinny pieces of information, you can narrow the column to let it just fit the data as desired. There are various techniques you can follow to widen or narrow a column. To change the width of a column: you can position the mouse on the right border of a column header. The mouse pointer would change into a horizontal double arrow crossed by a vertical line: If you double-click, the column would be resized to the widest value of the column, provided the widest value is wider than the column header. If the widest value is narrower than the column header, the column width would be widened enough to display the name of the column. You can click the column's right border and drag in the desired direction, left or right until you get the desired width You can right-click a column's name and click Column Width... This would open the Column Width dialog box where you can type the desired value and click OK Moving a Column If you find out that a particular column is misplaced in a table, you can change its position. To move a column in Datasheet View, first select it. Click and hold your mouse on it. Then, start dragging left or right in the desired direction. While your mouse is moving, a thick vertical line will guide you. Once the vertical line is positioned to the desired location, release the mouse: To move a group of columns, first select them as we reviewed earlier. Click and hold the mouse on one of the selected columns. Start dragging left or right in the desired direction until the thick vertical guiding line is positioned in the desired location, then release the mouse: Inserting a Column Inserting a column consists of adding one between two existing fields. To do this, right-click the column that will succeed it and click Insert Field Practical Learning: Inserting a Column The Clarksville Ice Cream database should still be opened. In the Navigation Pane, double-click the Customers Orders to open the table To add a new field, right-click the Order Date column header and click Insert Field Click the cell under Order Time In the Add & Delete section of the Ribbon, click Text Renaming a Column To rename a column, you must put it into edit mode. To do this: Double-click the name of the column in the header Right-click the column's name and click Rename Field Once the name is in edit mode, type the desired name and press Enter. Practical Learning: Renaming a Column The Clarksville Ice Cream database should still be opened. Right-click the Field1 column header and click Rename Field Type Clerk and press Enter Right-click Field2 and click Rename Field Type Flavor and press Enter Close the table Hiding and Revealing a Hidden Column If a table contains many columns and at one time you think you don't need all of them, you can hide some. To hide a column, you can drag the right border of its column header completely to its left border as we saw earlier to change the width of a column; when the vertical guiding line reaches the left border, release the mouse: the column would be hidden from the table:   To hide one or a group of columns, you can right-click and click Hide Fields. You can also right-click any column and click Unhide Fields. This would open the Unhide Columns dialog box. Here is an example: To hide a column, clear its check box. To reveal a column or a group of columns previously hidden, right-click any column header on the table and click Unhide Column. In the Unhide Columns dialog box, put a check mark on each column you want to show. Deleting a Column If you have an undesirable column in a table, you can delete it. It is important to keep in mind that if you delete a column, it also goes with any information under it. To remove a column from a table: Right-click the column's name and click Delete Field Select the column (or a group of columns), right-click anywhere in the table and click Delete Field Select a column (or a group of columns). Then, in the Add & Delete section of the Ribbon, click the Delete button Any of these actions would present you a warning to confirm whether you still want to delete the column(s) or you want to change your mind. If you still want to remove the column(s), click Yes. Lesson Summary    Exercises   Yugo National Bank Create a blank database and name it Yugo National Bank1 Double-click Add New Field and type AccountType Add one more column named  Description  Change ID to AccountTypeID Save the table as AccountTypes Watts A loan Create a blank database and name it Watts A Loan1 After the default ID column, create the following additional columns: FirstName, MiddleName, LastName, Address, City, State, ZIPCode, Country, HomePhone, WorkPhone, EmailAddress, and Notes Rename the ID column as CustomerID,  Save the table as Customers