WEBVTT Kind: captions Language: en 00:00:14.360 --> 00:00:16.609 modify fields in your tables. 00:00:16.609 --> 00:00:18.589 Access makes it easy to do this, 00:00:18.589 --> 00:00:21.789 although there are some important things that you'll need to consider. 00:00:21.789 --> 00:00:23.859 There are three different rules that you can apply 00:00:23.859 --> 00:00:25.980 to control the type of data that the fields can 00:00:25.980 --> 00:00:27.029 accept. 00:00:27.029 --> 00:00:30.220 And these are data types, character limits, and 00:00:30.220 --> 00:00:33.010 validation rules. 00:00:33.010 --> 00:00:34.870 To get started, make sure that you have a table 00:00:34.870 --> 00:00:35.449 open. 00:00:35.449 --> 00:00:38.219 I'm using the Customers table. 00:00:38.219 --> 00:00:40.120 We're going to scroll all the way to the right 00:00:40.120 --> 00:00:44.329 until you see the blank field that says Click to Add. 00:00:44.329 --> 00:00:46.039 And when you click on it, you'll see a list of all 00:00:46.039 --> 00:00:49.019 of the data types that you can choose from. 00:00:49.019 --> 00:00:51.660 Text is the default option, and this is the type 00:00:51.660 --> 00:00:53.460 that you'll use for regular text, 00:00:53.460 --> 00:00:56.019 such as a person's name or address. 00:00:56.019 --> 00:00:58.129 You'll also use it for numbers that aren't used in 00:00:58.129 --> 00:01:01.570 calculations, like a phone number or zip code. 00:01:01.570 --> 00:01:06.020 For any numbers that you might want to do calculations with, you'll need to choose Number. 00:01:06.020 --> 00:01:10.110 For example, you would use this for the quantities of an item that were sold. 00:01:10.110 --> 00:01:12.030 If you're dealing with money, then you'll choose 00:01:12.030 --> 00:01:13.450 Currency. 00:01:13.450 --> 00:01:17.280 And if you choose Date & Time, then when you're editing that field you'll see a calendar icon 00:01:17.280 --> 00:01:19.770 which you can click to select a date. 00:01:19.770 --> 00:01:22.240 But in this case, I just want a simple Yes or No 00:01:22.240 --> 00:01:24.700 answer, so I'll choose this one. 00:01:24.700 --> 00:01:27.250 And this adds a checkbox for each record. 00:01:27.250 --> 00:01:29.860 Then, you can type in the name of your field. 00:01:29.860 --> 00:01:34.180 I'm going to name it 'Add to Mailing List?' Then 00:01:34.180 --> 00:01:37.840 I'll resize this field. 00:01:37.840 --> 00:01:40.140 Now we can just check each customer who wants to 00:01:40.140 --> 00:01:42.950 be on our mailing list. 00:01:42.950 --> 00:01:44.899 And you can also click and drag the name to move 00:01:44.899 --> 00:01:47.610 the field wherever you like. 00:01:47.610 --> 00:01:49.610 If you decide that you need a different data type 00:01:49.610 --> 00:01:50.560 for a field, 00:01:50.560 --> 00:01:54.439 then you can just select it, and then go to the Fields tab 00:01:54.439 --> 00:01:57.619 and click the Data Type drop-down arrow. 00:01:57.619 --> 00:01:59.820 I'm going to change this to text so that I can add 00:01:59.820 --> 00:02:02.890 additional information in this field. 00:02:02.890 --> 00:02:04.719 Some of our customers want to receive our weekly 00:02:04.719 --> 00:02:05.850 newsletter, 00:02:05.850 --> 00:02:09.200 but others just want to hear about our special events. 00:02:09.200 --> 00:02:11.120 Now you should be very careful about changing the 00:02:11.120 --> 00:02:12.010 data type 00:02:12.010 --> 00:02:16.340 because it is possible to lose some of your data if you change it to the wrong type. 00:02:16.340 --> 00:02:18.370 In some fields, you may want to narrow down the 00:02:18.370 --> 00:02:21.340 data even further by adding a character limit. 00:02:21.340 --> 00:02:24.069 And you can only do this with text fields. 00:02:24.069 --> 00:02:25.950 For example, we want all of the states to be 00:02:25.950 --> 00:02:27.730 formatted the same way, 00:02:27.730 --> 00:02:31.319 so we're only using the two-letter state abbreviations. 00:02:31.319 --> 00:02:33.849 If some of the records say NC, and others say 00:02:33.849 --> 00:02:35.150 North Carolina, 00:02:35.150 --> 00:02:37.590 then Access won't know to group them together, 00:02:37.590 --> 00:02:41.480 which means our sorts, filters, and queries may not work right. 00:02:41.480 --> 00:02:44.620 In the Fields tab, find the field size box. 00:02:44.620 --> 00:02:48.500 The default field size is 255 characters, but I'm 00:02:48.500 --> 00:02:51.989 going to change it to 2. 00:02:51.989 --> 00:02:53.569 And you may get a warning message here, 00:02:53.569 --> 00:02:57.810 so if you're sure you want to change the field size, click Yes. 00:02:57.810 --> 00:03:00.700 In this case, setting a character limit isn't quite good enough 00:03:00.700 --> 00:03:04.920 because somebody could still type a two-letter code that's not a real state, 00:03:04.920 --> 00:03:06.940 for example NX. 00:03:06.940 --> 00:03:09.049 To prevent that, we need to be a lot more specific 00:03:09.049 --> 00:03:12.129 about what types of input this field will accept. 00:03:12.129 --> 00:03:15.150 And we'll do that by adding a validation rule. 00:03:15.150 --> 00:03:17.760 In the Fields tab, go to the Validation command on 00:03:17.760 --> 00:03:22.310 the far right, and select Field Validation Rule. 00:03:22.310 --> 00:03:25.769 Here, I'm going to type each state abbreviation in 00:03:25.769 --> 00:03:27.269 quotation marks, 00:03:27.269 --> 00:03:31.180 and I'm separating each one with the word 'Or'. 00:03:31.180 --> 00:03:34.159 And this may take a while. 00:03:34.159 --> 00:03:37.799 So this expression is just looking for exact matches, 00:03:37.799 --> 00:03:41.250 but if you want, you can create validation rules using the same syntaxes 00:03:41.250 --> 00:03:43.769 that we talked about in the query lessons. 00:03:43.769 --> 00:03:46.069 For example, you could use the Like syntax to set 00:03:46.069 --> 00:03:47.049 a validation rule 00:03:47.049 --> 00:03:49.470 that only allows text that ends with cake. 00:03:49.470 --> 00:03:51.799 Or, if you're using numerical values, 00:03:51.799 --> 00:03:57.049 you could use greater than to make sure that none of our quantities are negative. 00:03:57.049 --> 00:04:00.120 When you're done, click OK. 00:04:00.120 --> 00:04:04.720 Whenever you create a validation rule, it's important to create a validation message. 00:04:04.720 --> 00:04:08.239 And this option is also under the Validation command. 00:04:08.239 --> 00:04:10.500 This message will pop up whenever somebody tries 00:04:10.500 --> 00:04:11.040 to type in something 00:04:11.040 --> 00:04:13.489 that doesn't follow the validation rule. 00:04:13.489 --> 00:04:15.549 The message should briefly describe the rule, 00:04:15.549 --> 00:04:18.140 so that the user can then make the necessary corrections. 00:04:18.140 --> 00:04:20.250 In this case, I'll just mention that it needs to 00:04:20.250 --> 00:04:24.590 be a 2-letter abbreviation. 00:04:24.590 --> 00:04:28.600 You won't need to add a character limit or validation rule to all of your fields, 00:04:28.600 --> 00:04:31.910 but you can add one or both of them whenever you want to control the types of 00:04:31.910 --> 00:04:38.910 information that your field will accept.