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Mark the following statements as true or false.

1. The structure of the relationships in most databases follows only one model.

2. The relational model describes data using a standard tabular format.

3. Each attribute can take different values.

4. The tables in relational databases organize data in rows and columns.

5. Network models have become the most popular database models.

Put the letters in the following words into the correct order.

Fill in the blanks choosing from the variants given.

1.Hierarсhical and network models are still being used today, but … are the most popular.

a) relational models; b) network models; c) hierarсhical models

2. The allowable values for these attributes are called the … .

a) structure; b) table; c) domain

3. The tables in relational databases organize data … .

a) in columns; b)in rows and columns; c) in lines

4. These links dictate the way users can … data with application programs.

a) retrieve; b) handle; c) access

5. In the relational model, each row of table represents … , with the columns of the table representing attributes.

a) a data entity; b) database; c) warehouse

6. The relational model … data using a standard tabular format.

a) determines; b) describes; c) performs

Find the words to the given definitions.

1. a database model that describes data in which all data elements are placed in two-dimensional tables, that are the logical equivalent of files;

2. the allowable values for data attributes;

3. an expansion of the hierarchical database model with an owner-member relationship in which a member may have many owners;

4. a data model in which data is organized in a top-down, or inverted tree, structure;

5. a diagram of data entities and their relationships

Find the answers to the questions.

1. What are the most popular database models?

2. What do the tables in relational databases do?

3. Why does each model have unique advantages and disadvantages?

4. What do rows and columns represent in a relational model?

5. Can each attribute take on only certain values or different values?

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