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If missing, the following two features will also be missing; Reverse engineering - the ability to produce an ER diagram from a database, complete with foreign key relationships Yes - supports incremental reverse engineering, preserving user modifications to the diagram and importing only changes from the database
If a table includes an INTEGER PRIMARY KEY column, SQLite will typically optimize it by treating it as an alias for the rowid, causing the contents to be stored as a strictly typed 64-bit signed integer and changing its behavior to be somewhat like an auto-incrementing column. SQLite includes an option to create a table without a rowid column ...
Using a database-specific stored procedure that generates the surrogate key, performs the INSERT operation, and finally returns the generated key. For example, in Microsoft SQL Server, the key is retrieved via the SCOPE_IDENTITY() special function, while in SQLite the function is named last_insert_rowid().
A surrogate key (or synthetic key, pseudokey, entity identifier, factless key, or technical key [citation needed]) in a database is a unique identifier for either an entity in the modeled world or an object in the database. The surrogate key is not derived from application data, unlike a natural (or business) key. [1]
A column may contain text values, numbers, or even pointers to files in the operating system. [2] Columns typically contain simple types, though some relational database systems allow columns to contain more complex data types, such as whole documents, images, or even video clips. [3] [better source needed] A column can also be called an attribute.
All the candidate keys of a relation can uniquely identify the records of the relation, but only one of them is used as the primary key of the relation. The remaining candidate keys are called unique keys because they can uniquely identify a record in a relation. Unique keys can consist of multiple columns. Unique keys are also called alternate ...
A candidate key, or simply a key, of a relational database is any set of columns that have a unique combination of values in each row, with the additional constraint that removing any column could produce duplicate combinations of values. A candidate key is a minimal superkey, [1] i.e., a superkey that does not contain a smaller one. Therefore ...
An identity column differs from a primary key in that its values are managed by the server and usually cannot be modified. In many cases an identity column is used as a primary key; however, this is not always the case. It is a common misconception that an identity column will enforce uniqueness; however, this is not the case. If you want to ...