what is the difference between index and unique index?
457362
Differences. KEY or INDEX refers to a normal non-unique index. ... UNIQUE refers to an index where all rows of the index must be unique. That is, the same row may not have identical non-NULL values for all columns in this index as another row.
1468831
Rule 6: A Primary Index has a limit of 64 columns. A Unique Primary Index (UPI) is unique and cannot have any duplicates. If you try and insert a row with a Primary Index value that is already in the table, the row will be rejected. An UPI enforces UNIQUENESS for a column.
1336851
As adjectives the difference between unique and odd is that unique is {{context|not comparable|lang=en}} being the only one of its kind; unequaled, unparalleled or unmatched while odd is {{context|not comparable|lang=en}} single; sole; singular; not having a mate.
775422
Key Differences Between Primary key and Unique key: Primary key will not accept NULL values whereas Unique key can accept one NULL value. ... A Clustered index automatically created when a primary key is defined whereas Unique key generates the non-clustered index.
1182008
Clustered indexes are stored physically on the table. This means they are the fastest and you can only have one clustered index per table. Non-clustered indexes are stored separately, and you can have as many as you want. The best option is to set your clustered index on the most used unique column, usually the PK.
565379
While an index is a structure that is stored in database, keys are strictly a logical concept. Index help us in fast accessing a record, whereas keys just identify the records uniquely. Every table will necessarily have a key, but having an index is not mandatory.
1243222
The names of database objects need not be unique in a database. However, column names and index names must be unique within a table, and other object names must be unique for each owner within a database.
756936
As nouns the difference between index and appendix is that index is an alphabetical listing of items and their location while appendix is something attached to something else; an attachment or accompaniment.
829171
Index Numbers. What is the difference between simple index number and weighted index number? In the simple index number all items of the series are treated as of equal importance. In the weighted index, weights are accorded to different items depending on their relative importance.
126925
Primary key will not accept NULL values whereas Unique key can accept one NULL value. A table can have only primary key whereas there can be multiple unique key on a table. A Clustered index automatically created when a primary key is defined whereas Unique key generates the non-clustered index.
366125
An index is an indicator or measure of something, and in finance, it typically refers to a statistical measure of change in a securities market. In the case of financial markets, stock, and bond market indices consist of a hypothetical portfolio of securities representing a particular market or a segment of it.
1271831
That's because indexes are developed for a variety of purposes by many different entities, while benchmarks are chosen by people who want to be measured (such as portfolio managers) or by people who do the measuring (such as pension plans or plan consultants).
805033
The 'Unique ID' field is a setting which prevents the same value from being used in multiple records for any specific field. External IDs are often created with the 'Unique ID' setting so that the External IDs will be unique to each record.
829300
You can only have 1 primary key in a database table. ... You can have more than 1 unique key table column (unlike primary key which means only 1 table column in the table is unique). INDEX also creates uniqueness. MySQL (example) will create a indexing table for the column that is indexed.
959272
Both "indexes" and "indices" are acceptable plural forms of the word "index" or to refer to more than one index. Index is one of those rare words that have two different plurals in English. "Indices" is originally a Latin plural, while "Indexes" has taken the English way of making plurals, using –s or –es.
1293479
Here is the difference: SELECT SINGLE returns the first matching row for the given condition and it may not be unique, if there are more matching rows for the given condition. SELECT ... UP TO 1 ROWS retrieves all the matching records and applies aggregation and ordering and returns the first record.
825797
Difference between index and Abstract: Index Abstract An index consist of short indention of information with adequate bibliographical citation. Whereas an abstract consists of concise representation of an original document with adequate bibliographic details Index help to locate the required information.