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Tables can be set to inherit their characteristics from a parent table. Data in child tables will appear to exist in the parent tables, unless data is selected from the parent table using the ONLY keyword, i.e. SELECT * FROM ONLY parent_table;. Adding a column in the parent table will cause that column to appear in the child table.
For example, consider an address book entry that represents a single person along with zero or more phone numbers and zero or more addresses. This could be modeled in an object-oriented implementation by a "Person object " with an attribute/field to hold each data item that the entry comprises: the person's name, a list of phone numbers, and a ...
In the context of SQL, data definition or data description language (DDL) is a syntax for creating and modifying database objects such as tables, indices, and users. DDL statements are similar to a computer programming language for defining data structures , especially database schemas .
Major DBMSs, including SQLite, [5] MySQL, [6] Oracle, [7] IBM Db2, [8] Microsoft SQL Server [9] and PostgreSQL [10] support prepared statements. Prepared statements are normally executed through a non-SQL binary protocol for efficiency and protection from SQL injection, but with some DBMSs such as MySQL prepared statements are also available using a SQL syntax for debugging purposes.
Most relational database designs resolve many-to-many relationships by creating an additional table that contains the PKs from both of the other entity tables – the relationship becomes an entity; the resolution table is then named appropriately and the two FKs are combined to form a PK. The migration of PKs to other tables is the second ...
So far PostgreSQL is the only vendor to have announced a live product with this specific feature, in PostgreSQL 9.5. [ 3 ] [ 4 ] Other vendors have described some similar features, [ 2 ] including Oracle , [ 5 ] [ 6 ] Netezza 'zone maps', [ 7 ] Infobright 'data packs', [ 8 ] MonetDB [ 9 ] and Apache Hive with ORC/Parquet.
Table alignment}} can be used to align the cells in a whole column without adding code to each cell. For example, left aligning the first column, and center aligning the fourth column. For example, left aligning the first column, and center aligning the fourth column.
Yes, scripting of pages using Python and other programming languages No No Yes Yes [67] DokuWiki: Yes, plugin available Yes, RSS/Atom [68] Yes, to xml, text, html pages, LaTeX, Open doc format, pdf with plugins [69] Yes, plugin API Yes Yes Yes Yes [70] Section Editing, XHTML-Compliant, tables, side-by-side diff, namespaces, Interwiki FlexWiki ...