Unique integer

The comparison For identity of chemical structures is peiTormed on the basis of a hashcode algorithm, Hashcode are unique integer numbers which can be calculated for each chemical structure within the WODCA system [55], Further exam-... 

Each cluster has a unique, integer cluster label in and the vector p... 

A general rule is this Keep each table as simple as possible, with the fewest number of columns, each of which is essential to describe the entity (e.g., sample, compound, or chemist). Assign a unique integer id column and use that id in relationship to other tables containing more information or related information. 

Another commonly used constraint is the uniqueness constraint. In previous examples, the column compound id was defined to be a unique integer. When the uniqueness constraint is used in a table holding a collection of compounds, it ensures that there can never be more than one compound with a particular compound id. This is essential if other data about a compound are stored in other tables that use compound id as a foreign key. Notice that this does not prevent two identical compounds... 

The column structure.id is a unique integer relating the structure, sdf and property tables. The sdf.molfile column contains the molfile for each structure as defined by the vendor. The structure.name and structure.cansmiles columns contain the name and canonical smiles parsed and computed from the molfile. The structure.coord column will contain an array of atomic coordinates. The structure, atom column will contain an array of atom numbers from the file in canonical order to correspond to the atom order in the canonical SMILES. The OpenBabel/plpythonu extension functions molfile mol and molfile properties will be used to parse the vendor SDF molfiles and populate these tables. The molfile column of the sdf table is first populated from the SDF file, using the following perl script. 

At this point, the vla4.sdf table has been created in the database named mydb. The molfile column contains the molfile for each structure in the sdf file. The sdf. id column contains a unique integer that can be used to relate the vla4.property table. Notice the use of the default value nextval( vla4.structure id sql ) in the SQL statement that creates the vla4. sdf table. This causes the sdf. id column to contain... 

This introduces a new way in which sequences are used within a database. In previous chapters, the Serial data type was used to create a column of unique integers. When the Serial data type is used, a sequence is automatically created and the default value of the column is set to be the next value in the sequence. In this way, a unique set of integers is ensured. In the above example, more control is needed over the use of sequence values in the sample. id column. This is because this table may contain several rows with the same sample id, each with a different compound id. The sample consists then of all compounds in the sample table having the same sample id. 

Note that X is now a concentrated scheme. We proceed by induction on the unique integer n = n X) such that X can be covered by n quasi-compact separated open subschemes, but not by any n — 1 such subschemes. (This integer exists because X is quasi-compact and its affine open subschemes are quasi-compact and separated.)... 

Theorem 2,2.11 (Division Algorithm). For any two integers x and y, where y > 0, there exist unique integers q and r such that... 

Analysis. The Division Algorithm states that for any two integers x and y, where j/ > 0, there exist unique integers q and r such that x = q-y+r, where 0 < r < j/— 1. Write an essay that explains why the quotient q and the remainder r are unique. This can be done by taking two specific values for x and y. say x = 157 and y = 25, and showing why the quotient and the remainder obtained when 157 is divided by 25 are unique. 

Bob must find the unique integer s such that 1 < s < m and... 

We solve (6.12) numerically using the method of finite differences, encountered earlier in Chapters 1 and 2. We place a regular grid of points as shown in Figure 6.2. To the point at (Xi, yf), we assign a unique integer label n = (Y - 1)W + j. The neighboring points, and their labels, are... 

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