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help1402

This forum is provided to promote discussion amongst students enrolled in CITS1402 Relational Database Management Systems.

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 UWA week 31 (2nd semester, week 2) ↓
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Hi all, I have 2 questions concerning lab 1. 1. There are several inconsistencies regarding the data types in the requirements and expected outcomes. To pass the auto test: `street`,`city`,`postcode` columns in Q1 should be type `VARCHAR` instead of `CHAR` `position` column in Q2 should be type `VARCHAR` instead of `CHAR` Could anyone please clarify which data type should be used for submitting answers? 2. I've read on stackoverflow that we do not need to specify "not null" for primary keys, but this is not the case for me. I had to add the `NOT NULL` constraints manually for the `notnull` flags to be 1. Does anyone know why this is happening? Thanks!


 UWA week 32 (2nd semester, week 3) ↓
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There were a few issues regarding the question text referring to the wrong data type, those have been fixed, each question that involved creating attributes will mention the required type and length due to very specific checking of output enabled. While you can have no NOT NULL for primary keys, it's not the best practice, if you imagine that the primary key is the only way of returning any specific record, allowing the key to be NULL allows for multiple rows to return on the occurrence of a NULL key, defeating the purpose of having a key to uniquely identify records. The penalties for the first lab have been removed, so there is some flexibility to deal with minor text differences such as this, but for subsequent labs, please remember to use exactly what is mentioned in the question text, such as specific data types length of attributes, names of attributes etc. Thanks, Adam. ANONYMOUS wrote:
> Hi all, > > I have 2 questions concerning lab 1. > > 1. There are several inconsistencies regarding the data types in the requirements and expected outcomes. > > To pass the auto test: > `street`,`city`,`postcode` columns in Q1 should be type `VARCHAR` instead of `CHAR` > `position` column in Q2 should be type `VARCHAR` instead of `CHAR` > > Could anyone please clarify which data type should be used for submitting answers? > > 2. I've read on stackoverflow that we do not need to specify "not null" for primary keys, but this is not the case for me. I had to add the `NOT NULL` constraints manually for the `notnull` flags to be 1. Does anyone know why this is happening? > > Thanks!

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