As a NoSQL database, the syntax of tcapsusdb is different from that of traditional SQL relational database. This paper will introduce the concept and meaning of the three common terms in tcapsusdb: table, record and index.
Terms / concepts
First of all, the comparison of tcapsusdb with SQL database and mongodb terms is shown in the following figure:
| SQL terms / concepts | Mongodb terms / concepts | Tcapsusdb terms / concepts | Explanation / explanation |
|---|---|---|---|
| database | database | cluster | database |
| table | collection | tablegroup/table | Database tables / collections |
| row | document | record | Data record line / document |
| column | field | field | Data field / field |
| index | index | index | Indexes |
| primary key | primary key | primary key | Primary key, mongodb will automatically_ The ID field is set as the primary key |
Comparison of tcapsusdb syntax
surface
Tcapsusdb table consists of two parts: primary key field and non primary key field. The maximum number of primary key field can be 8, and the maximum number of common field (non common field) can be 256.
Diagram of tcapsusdb primary key field
record
Tcapsusdb records consist of a line of strings, and the number of each field supports nested type, with up to 32 levels of nesting. The maximum size of a single record is 10MB, and the commonly used object files can be serialized into binary files for storage.
The difference between the general record and the large record in tcapsusdb
Indexes
Tcapsusdb supports two kinds of indexes: local index and distributed index. The local index needs to be specified when the table is created. The distributed index supports modification at any time. It can specify either primary key field or common field. Index is widely used in conditional query, fuzzy matching, range search and other scenarios.
Two indexes supported by tcapsusdb
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Tcapsusdb is a distributed NoSQL database produced by Tencent. The code for storage and scheduling is completely self-developed. It has the characteristics of cache + landing fusion architecture, Pb level storage, millisecond delay, lossless horizontal expansion and complex data structure. At the same time, it has the characteristics of rich ecology, convenient migration, extremely low operation and maintenance cost and five nine high availability. Customers cover games, Internet, government affairs, finance, manufacturing and Internet of things.