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Hi/Lo is an algorithm and a key generation strategy used for generating unique keys for use in a database as a primary key. It uses a sequence-based hi-lo pattern to generate values. Hi/Lo is used in scenarios where an application needs its entities to have an identity prior to persistence. It is a value generation strategy.
Like nodes, relationships can also have properties. [4] Labels can group similar nodes together by assigning zero or more node labels. Labels are kind of like tags and allow you to specify certain types of entities to look for or create. Properties are key-value pairs with a binding of a string key and some value from the Cypher type system.
The Oracle Database SYS_GUID function does not return a standard GUID, despite the name. Instead, it returns a 16-byte 128-bit RAW value based on a host identifier and a process or thread identifier, somewhat similar to a GUID. [34] PostgreSQL contains a UUID datatype [35] and can generate most versions of UUIDs through the use of functions ...
The SQL language is subdivided into several language elements, including: Keywords are words that are defined in the SQL language. They are either reserved (e.g. SELECT, COUNT and YEAR), or non-reserved (e.g. ASC, DOMAIN and KEY). List of SQL reserved words. Identifiers are names on database objects, like tables, columns and schemas. An ...
In computer science, a generator is a routine that can be used to control the iteration behaviour of a loop.All generators are also iterators. [1] A generator is very similar to a function that returns an array, in that a generator has parameters, can be called, and generates a sequence of values.
Query by Example (QBE) is a database query language for relational databases. It was devised by Moshé M. Zloof at IBM Research during the mid-1970s, in parallel to the development of SQL . [ 1 ] It is the first graphical query language, using visual tables where the user would enter commands, example elements and conditions.
SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd [12] in the early 1970s. [13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasirelational database management system, System R, which a group at IBM San ...
Lemon is a parser generator, maintained as part of the SQLite project, that generates a look-ahead LR parser (LALR parser) in the programming language C from an input context-free grammar. The generator is quite simple, implemented in one C source file with another file used as a template for output. Lexical analysis is performed externally.