| Beide Seiten der vorigen Revision Vorhergehende Überarbeitung Nächste Überarbeitung | Vorhergehende Überarbeitung |
| modul:m290:learningunits:lu03:loesungen:l01 [2024/08/14 14:06] – vdemir | modul:m290:learningunits:lu03:loesungen:l01 [2024/10/17 12:32] (aktuell) – vdemir |
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| ====== LU03.L01 - Choose data-types ====== | ====== LU04.S01 - Choose data-types ====== |
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| Which datatype would you use to store the following information? Give reason for your decision. | Which datatype would you use to store the following information? Give reason for your decision. |
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| * product-title like trousers up to 50 characters: | 1. Product-title like trousers up to 50 characters: |
| *<color #ed1c24>VARCHAR(50)</color> | *<color #ed1c24>VARCHAR(50)</color> |
| *<color #ed1c24>Titles can be at the most 50 characters. A fix length makes no sense in that case. </color> | *<color #ed1c24>Titles can be at the most 50 characters. A fix length like a simple CHAR(50) makes no sense in that case. </color> |
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| * product-description up to 255 characters: | 2. Product-description up to 255 characters: |
| *<color #ed1c24>VARCHAR(255)</color> | *<color #ed1c24>VARCHAR(255)</color> |
| *<color #ed1c24>The description can be 255 characters, but can also be shorter. A fix length does not make sense in that case. </color> | *<color #ed1c24>The description can be 255 characters, but can also be shorter. A fix length does not make sense in that case. </color> |
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| * stock amount: | 3. Stock amount: |
| * <color #ed1c24>INT or INTEGER</color> | *<color #ed1c24>INT or INTEGER</color> |
| * <color #ed1c24>Floating point type is not suitable as pieces are always counted in whole numbers. </color> | *<color #ed1c24>Floating point type is not suitable as pieces are always counted in whole numbers. </color> |
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| * price of each piece: | 4. Price of each piece: |
| * <color #ed1c24>FLOAT(5,2) or DECIMAL(U5,2)</color> | *<color #ed1c24>FLOAT(6,2) or DECIMAL(6,2)</color> |
| * <color #ed1c24>Prices have floating point</color> | *<color #ed1c24>Prices have floating point</color> |
| * <color #ed1c24>The length of (5,2) should be sufficient enough as trousers are usually within a price ranger of 0.99 to 999.99. </color> | * <color #ed1c24>The length of (6,2) should be sufficient enough as trousers are usually within a price ranger of 0.99 to 9999.99. </color> |
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| * order date: | 5. Order date: |
| * <color #ed1c24>DATE or DATETIME</color> | *<color #ed1c24>DATE or DATETIME</color> |
| * <color #ed1c24>The type depends on whether we want to safe only the date, but also the time. </color> | *<color #ed1c24>The type depends on whether we want to safe only the date, but also the time. </color> |
| * <color #ed1c24>Usually in such cases to store only the order-date is enough.</color> | *<color #ed1c24>Usually in such cases to store only the order-date is enough.</color> |
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| * date of delivery: | 6. Date of delivery: |
| * <color #ed1c24>DATETIME or TIMESTAMP</color> | *<color #ed1c24>DATETIME or TIMESTAMP</color> |
| * <color #ed1c24>Regarding delivery quality the criteria punctuality might be one key element. Therefore the storage of the delivery-time is compulsory.</color> | *<color #ed1c24>Regarding delivery quality the criteria punctuality might be one key element. Therefore the storage of the delivery-time is compulsory.</color> |
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| * organical or not: | 7. organic or not: |
| * <color #ed1c24>BOOLEAN</color> | *<color #ed1c24>BOOLEAN</color> |
| * <color #ed1c24>As there a only two possibilites to store a boolean data-type is the correct data-type. </color> | *<color #ed1c24>As there a only two possibilites to store a boolean data-type is the correct data-type. </color> |
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| * usage category with only one character: | 8. Usage category with only one character: |
| * <color #ed1c24>CHAR</color> | * <color #ed1c24>CHAR</color> |
| * <color #ed1c24>As long as there is only one character to be stored the CHAR-type will work. </color> | * <color #ed1c24>As long as there is only one character to be stored the CHAR-type will work. </color> |
| * <color #ed1c24>Technically the CHAR-types allows all letters, digits (as letters) and special characters.</color> | * <color #ed1c24>Technically the CHAR-types allows all letters, digits (as letters) and special characters.</color> |
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| ===== Vocabulary ===== | ===== Vocabulary ===== |