When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. Data cleansing - Wikipedia

    en.wikipedia.org/wiki/Data_cleansing

    Set-Membership constraints: The values for a column come from a set of discrete values or codes. For example, a person's sex may be Female, Male, or Non-Binary. Foreign-key constraints: This is the more general case of set membership. The set of values in a column is defined in a column of another table that contains unique values.

  3. Table (database) - Wikipedia

    en.wikipedia.org/wiki/Table_(database)

    In a database, a table is a collection of related data organized in table format; consisting of columns and rows. In relational databases , and flat file databases , a table is a set of data elements (values) using a model of vertical columns (identifiable by name) and horizontal rows , the cell being the unit where a row and column intersect ...

  4. Delete (SQL) - Wikipedia

    en.wikipedia.org/wiki/Delete_(SQL)

    Deleting all rows from a table can be very time-consuming. Some DBMS [clarification needed] offer a TRUNCATE TABLE command that works a lot quicker, as it only alters metadata and typically does not spend time enforcing constraints or firing triggers. DELETE only deletes the rows. For deleting a table entirely the DROP command can be used.

  5. Tab-separated values - Wikipedia

    en.wikipedia.org/wiki/Tab-separated_values

    The head of the Iris flower data set can be stored as a TSV using the following plain text (note that the HTML rendering may convert tabs to spaces): . Sepal length Sepal width Petal length Petal width Species 5.1 3.5 1.4 0.2 I. setosa 4.9 3.0 1.4 0.2 I. setosa 4.7 3.2 1.3 0.2 I. setosa 4.6 3.1 1.5 0.2 I. setosa 5.0 3.6 1.4 0.2 I. setosa

  6. Null (SQL) - Wikipedia

    en.wikipedia.org/wiki/Null_(SQL)

    E. F. Codd mentioned nulls as a method of representing missing data in the relational model in a 1975 paper in the FDT Bulletin of ACM-SIGMOD.Codd's paper that is most commonly cited with the semantics of Null (as adopted in SQL) is his 1979 paper in the ACM Transactions on Database Systems, in which he also introduced his Relational Model/Tasmania, although much of the other proposals from ...

  7. Comma-separated values - Wikipedia

    en.wikipedia.org/wiki/Comma-separated_values

    Comma-separated values (CSV) is a text file format that uses commas to separate values, and newlines to separate records. A CSV file stores tabular data (numbers and text) in plain text, where each line of the file typically represents one data record.

  8. Entity–attribute–value model - Wikipedia

    en.wikipedia.org/wiki/Entity–attribute–value...

    In an EAV data model, each attribute–value pair is a fact describing an entity, and a row in an EAV table stores a single fact. EAV tables are often described as "long and skinny": "long" refers to the number of rows, "skinny" to the few columns. Data is recorded as three columns: The entity: the item being described.

  9. Record (computer science) - Wikipedia

    en.wikipedia.org/wiki/Record_(computer_science)

    In the context of storage such as in a database or spreadsheet a record is often called a row and each field is called a column. [2] [3] [4] [5]In object-oriented programming, an object is a record that contains state and method fields.

  1. Related searches delete null rows pandas list columns number from table php string

    delete null rows pandas list columns number from table php string function