PostgreSQL Query Catalog

Find base table columns that belong to more than one index (including automatically created indexes that support constraints).

Find base table columns that contain only one value. Perhaps it is an unnecessary column. Having only one value is most likely inadequate for testing.

Find base table columns that do not have uuid type but the name of the column refers to the possibility that the values in the column are uuid's.

Find base table columns that have an enumerated type that seems to emulate Boolean type.

Find base table columns that have Boolean type and based on the column name are meant for recording data about gender.

Find base table columns that have Boolean type and do not have NOT NULL constraint. Use two-valued logic (TRUE, FALSE) instead of three-valued logic (TRUE, FALSE, UNKNOWN). Because NULL in a Boolean column means unknown make all the Boolean columns mandatory.

Find base table columns that have both default value determined through a domain and default value that is directly attached to the column. Do not duplicate specifications of default values to avoid confusion and surprises. If column and domain both have a default value, then in case of inserting data the default value that is associated directly with the column is used.

Find base table columns that have CHAR type, where character maximum length is bigger than 1 and the name of the column does not refer to the possibility that the column holds some kind of codes or flags or hash values.

Find base table columns that have FLOAT, REAL, or DOUBLE PRECISION type. "The data types real and double precision are inexact, variable-precision numeric types. On all currently supported platforms, these types are implementations of IEEE Standard 754 for Binary Floating-Point Arithmetic (single and double precision, respectively), to the extent that the underlying processor, operating system, and compiler support it." (PostgreSQL documentation) Do not use the approximate numeric types FLOAT, REAL, and DOUBLE PRECISION in order to present fractional numeric data. Due to the use of the IEEE 754 standard the results of calculations with the values, which have one of these types, can be inexact because out of necessity some numbers must be rounded to a value, which is very close. "Comparing two floating-point values for equality might not always work as expected." (PostgreSQL documentation)

Find base table columns that have the DECIMAL/NUMERIC type, but do not have precision and scale specified. "Specifying: NUMERIC without any precision or scale creates a column in which numeric values of any precision and scale can be stored, up to the implementation limit on precision. A column of this kind will not coerce input values to any particular scale, whereas numeric columns with a declared scale will coerce input values to that scale."

Find base table columns that have the same name and type but different field size.

Find base table columns that have the same name as the domain name or the data type name of the column. The names may have different uppercase/lowercase characters. Columns, domains, and types are different concepts in SQL and perhaps it is better to use different names in case of these.

Find base table columns that have type NUMERIC and the scale is 0, i.e., one can record in the column only integer values. Arithmetic operations are slower in case of the numeric type compared to an integer type. Thus, in order to record integer values, one should use columns with the type SMALLINT, INTEGER, or BIGINT instead of NUMERIC(p,0).

Find base table columns that name refers to the possibility that the column is used to record names or textual descriptions but the column seems to have a simple check constraint that restricts spaces in these.

Find base table columns that name refers to the possibility that there are registered deadlines but the column does not have a temporal type.

Find base table columns that name refers to the possibility that these are used to register comments/descriptions. Find the columns where the data type is not VARCHAR and TEXT or in case of VARCHAR the maximum number of permitted characters is smaller than 1000. In case of determining field sizes choose a size that permits registration of all possible legal values.

Find base table columns that name refers to the possibility that these are used to register data about prices/sums of money. Find the columns that have decimal type but have a too big (bigger than six) or a too small scale (zero). The selection of field size must be precise and should take into account the possible data in the column.

Find base table columns that name refers to the possibility that these are used to register dates. Find the columns that do not have an appropriate data type. Column names should reflect the data that is possible to record in the column. For instance, in case of temporal data the column name should indicate as to whether we record dates or timestamps. If the column data type is "date", then the suffix of the column name should be "kp" (Estonian) or "date" (English).

Find base table columns that name refers to the possibility that these are used to register file/web addresses. Find the columns where the type refers to the possibility that values in the column are actual files.

Find base table columns that name refers to the possibility that these are used to register names. Find base table columns that name refers to the possibility that these are used to register comments/descriptions/etc. Find the cases where a base table contains columns from the both sets and the field size in case of the latter is not at least twice as big as in case of the former. For example, if the name of a service can be 100 character long, then it is quite illogical that the description of the service is only at most 200 characters long.