Logic Gates and How many types of Logic Gates in Circuits
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A logic gates are basic block for digital circuits. Most of the logic gates consists of 2 inputs and one output. While in operation a logic gate terminal/point is in two binary conditions low (0) or high (1), having different voltage levels. When a circuit starts processing data the terminal change it's state and change often. Most of the logic gates approximately have 0 volts (0 V), while the high state is approximately five volts positive (+5 V).
There are seven basic logic gates: AND, OR, XOR, NOT, NAND, NOR, and XNOR.
AND GATE:
The AND gate is so named because, if 0 is called "false" and 1 is called "true," the gate acts in the same way as the logical "and" operator. The following illustration and table show the circuit symbol and logic combinations for an AND gate. (In the symbol, the input terminals are at left and the output terminal is at right.) The output is "true" when both inputs are "true." Otherwise, the output is "false."
Data Consistency: Definition 1: Data consistency means that the changes made to the different occurrences of data should be controlled and managed in such a way that all the occurrences have the same value for any specific data item. Data inconsistency leads to a number of problems, including loss of information and incorrect results. In the database approach, it is controlled because data is shared and consistency is controlled and maintained. Data Consistency Definition 2: Data consistency meaning is the validity, accuracy and usability of related data. It ensures that each user observes a consistent(Same) view of the data, including changes made by the user’s own transactions and transactions of other users. Types of Data Consistency: Point in time consistency Transaction consistency Application consistency Data Inconsistncy: Data Inconsistency Definition: Data inconsistency meaning is that different versions of the same data appear in d...
Logical Relationship in Tables: Database tables have a major advantage to bridge them with some logical relationship so to filter the records. These relationship allowed us to access one table data using another table records(via columns or rows). In other words logical filtration is called cardinality DBMS. Read Also: Relational Model in DBMS Definitions of Cardinality in DBMS: Definition 1: A number that represents, one instance of first entity(table) is related to how many instances of the second entity, is known as cardinality in dbms. Definition 2: Cardinality is a relationship or join/bridge between rows of 1 table to the rows of another table. via some column (e.g. User Table column {user_id} in another table Posts to filter the posts by user_id). Types of Cardinality in DBMS: There are three types of Cardinality in DBMS. one-to-one one-to-many many-to-one many-to-many Read Also: Degree of Relationship in DBMS ...
"null 'means" unknown data "or" non-existent value ". Sometimes, the data corresponding to a field of a record may be unknown or not exist. In these cases we say that the field can contain null values. For example, in our table of books, we can have null values in the "price" field because it is possible that for some books we have not set the price for sale. In contrast, we have fields that can never be empty. Let's look at an example. We have our table "books". The "title" field should never be empty, likewise the "author" field. To do this, when creating the table, we must specify that such fields do not allow null values: create table books ( title varchar2 (30) not null, author varchar2 (20) not null, editorial varchar2 (15) null, price number (5.2) ); To specify that a field does NOT allow null values, we must put "not null" after the field definition. In the above example, the "p...
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